F 355 
YU 



IN ?KACllC£ AND 



Hollinger Corp. 
pH8.5 



I!!! 

: • 



A STUDY 

IN PRACTICE AND 

HABIT 



AN INVESTIGATION INTO MOTOR CO-ORDINATION IN ITS 
RELATION TO ATTENTION, ASSOCIATION, MODI- 
FICATION, REPETITION AND HABIT 



BY 
WALTER JORGENSEN YOUNG, A. M. 



A Thesis Presented to the Faculty of the Graduate School of the University 
of Pennsylvania in partial fulfilment of the requirements 

for the 
Degree of Doctor of Philosophy 



1911 



Richmond Press, Inc., Printers 



S-F33 5 

a 



Y6 



C.3 



f/ 



PREFACE. 



The thesis herewith presented is the outgrowth of the author's pri- 
mary interest in the moral aspect of Habit. Instrumental research in 
this field proved deficient in exact recording apparatus. The author, 
having defined the requirements of the needed instrument and outlined 
its general nature, then designed the instrument in co-operation with 
Prof. E. B. Twitmyer, Asst. Director of the Psychological Laboratory at 
the University of Pennsylvania, to whose superior knowledge of electrical 
apparatus he is indebted in constructing the instrument. The auto- 
matic adjustment apparatus is the suggestion of Prof. Twitmyer. 



C&rnszu Institution 
of Washington 
1913 



CONTENTS: 



Page 

Preface 2 

Introduction 3 

Review 3 

Method of Procedure 5 

Description of Instrument 8 

Experiment I, Single Action of Digits, 

Description and Results 11 

Discussion of Results 19 

1 . Analysis of Errors 19 

2. Analysis of Time Element 22 

Experiment II, Double Action of Digits, 

Description and Results 24 

Analysis of Results 27 

Experiments III and IV, Successive Action of Digits, 

Description and Results 28 

Analysis of Results 36 

1 . Distraction 36 

2. The transition stages 36 

3. Theory of organic selection 37 

4. Errors of duplication 39 

5. Sight and Touch methods compared 39 

6. Breakdown stages 40 

7. Errors of Omission 40 

8. Errors of Out-of-order 41 

9. Touch sensations in system of control 41 

10. "Cross-Education" 44 

11. The Practice Curve 45 

12. The "plateaus" 45 

General Conclusions 46 

Bibliography 48 



A Study in Practice and Habit. 



INTRODUCTORY. 

Recent investigation has largely expanded studies in practice and 
habit, which as yet present a field but slightly developed. The pres- 
ent status shows lack of uniformity in method and technique, and 
crudity of instrumental research. A corresponding ambiguity arises 
in the meaning of Practice. One view presents practice as an associa- 
tion of the stimulus (the end set up) with the appropriate response, 
and habit is consequently studied as a problem of association. The 
other conception views practice as an adjustment of movements, co- 
ordinated to meet the appropriate stimulus. One bears toward the 
psychological, the other toward the physiological aspect of practice 
and habit. Both theories adopt the method of expression, the first 
seeking to multiply the stimuli; the second to secure more accurate 
records of results. Admitting both to be partial views of a whole, 
the present thesis bears more directly toward the physiological aspect 
of experimentation in habit-formation, confining the former more 
properly to memory and association, as related to practice. The 
endeavor here is to present more accurate recording instruments, a 
tentative technique for such investigations, and an analysis of results 
in the light of the experiments following. 

Ebbinghaus (1) in 1887 gave a great stimulus to the study of prac- 
tice in the realm of memory investigation. Muller and Schuman (2), 
Meumann, (3) and others expanded this work, using nonsense 
syllables, figure combinations, and the like. T. L. Smith (July, 1896) 
published an article on Muscular Memory (4), suggesting that "the 
influence of the muscular and motor element in memory might be 
reduced to a laboratory problem and investigated by experimental 
methods." An automatic shutter arrangement was used in connec- 
tion with movements of 1. throat, tongue and lips, and 2. movements 
of the hand (hand-writing). Errors were recorded under three heads: 
1. displacements; 2. wrong syllables; 3. forgotten syllables. Averages 
with mean variations were used in plotting practice curves, suggesting 
methods of tabulation and diagraming followed by all the later in- 
vestigators in the study of practice. 

The foregoing investigations afforded a general stimulus to experi- 
mentation in 1. the relation of practice and habit; 2. the acquisition 
of skill in some occupation; 3. specific points in the general field of 
habit formation. Johnson in his tapping experiments (5) suggested 
that the relation of regularity to reaction-time constitutes the criteria 

(1) Ueber das Gedachtniss, Rev. Am. Journ. Pay., 1888-9, p. 557. 

(2) Experimental Beitrage zur Untersuchung, etc., Zeit. f. Psy., VI., 2 and 3, p. 
173. 

(3) Kuhlmann, "Present Status of Memory Invest.", Rev. Psy. Bull. V., 1908, p. 
285 

' (4) Am. Journ. Psy., 1896, VII., p. 453. 
(5) Yale Psy. Studies, VI., p. 51. 



4 A Study in Practice and Habit. 

of general improvement from practice. Practice follows a general 
mathematical law of constant increase as do falling bodies, though the 
law is not stated. Bryan and Harter in Studies of the Telegraphic 
Language (1) endeavored to construct a theory of that occupation, 
as a "hierarchy of habits." Davis in cross-education shows how far 
it is possible that one set of habits may influence the formation of 
another set. MacMillan (2) studied the effect of change of the visual 
series by means of deflecting prisms on the readjustment of habitual 
co-ordinations, concluding that "the control of habit in its formation 
and use comes from the end set up." Raif in his Fingerfertigheit (3) 
concluded that piano practice is concerned not so much with finger 
nimbleness as association quickness, hence special attention should 
be given to the sensory and perceptional rather than the peripheral 
and functional end of habit. Bourdon (4) found that habits formed 
by special practice persisted after a lapse of seven years. 

Woodworth, investigating the relation of voluntary movements to 
sensory stimuli, concluded that voluntary movements are controlled 
by association of a given stimulus with a given response. (5) Downey 
took up the study of Control Processes in modified handwriting (6) , 
giving a complete analysis of the psychological factors involved 
and pointing out the various functional movements resorted to under 
distraction and extremes of interference with the habitual order. 
Coover and Angell (7) add nothing in the general practice effect of 
special exercise to the conclusions of Davis. Bair in The Practice 
Curve (8) studied typewriting skill with special reference to response 
of a given movement to a given stimulus. Upon his analysis of the 
so-called practice curve, he constructs a physiological theory of the 
processes involved in these movements, concluding that the whole 
of our mental life is governed by our habitual bodily attitudes. "From 
the standpoint of this (motor) element we have already discussed 
association, discrimination, memory, sleep and dreams, habit, disposi- 
tion, interest and attention, mental content, and the trend of thought. 
On this same basis, reasoning, imagination, and the other mental 
processes could be accounted for." (9) In a series of articles, Swift 
gives various aspects of the Psychology and Physiology of Learning (10) 
such as ball-tossing, short-hand skill and typewriting. Introspec- 
tion and observation were used to supplement records in explaining 
results, thus suggesting the lines along which Book in his study of the 
Acquisition of Skill (11) in typewriting proceeded in his analysis of 
the psychology of that occupation. Both these latter, depending 

(1) Psy. Rev., IV., 1897, p. 27; VI., 1899, p. 345. 

(2) U. of Chicago contr. to Phil., 1899, II., No. 2, p. 11. 

(3) Zeit. f. Psy., 24, 1900, p. 352. 

(4) L'Annee Psy., VIII., 1901, p. 327. 

(5) "Accuracy of a Voluntary Movement." 

(6) Psy. Rev. sup. No. 37. 

(7) Am. Journ. Psy., XVIII, 1907, p. 328. 

(8) Psy. Rev. sup. V., No. 2, 1902. 

(9) P. 64. 

(10) Am. Journ. Psy., 1903, p. 201; Psy. Bull., I, 1904, p. 295; IV, 1907, p. 307. 

(11) U. of Montana Pub., Psy. Series No. 1, 1908. 



A Study in Practice and Habit. 5 

on complex programs of introspection studied the psychological ac- 
companiments, and hence the problem was resolved into a study of 
association, concerning themselves less with the intimate relation of 
practice to co-ordinated complexes of response in movement. 

Habit is concerned with response to a stimulus in complexes of 
movement in a given time-order series. These complex movements 
involve co-ordinations of varying degrees of organization from simple 
to complex. Johnson, Woodworth and Downey found that control 
processes reside in co-ordinations of movement rather than processes 
of association. From the genetic viewpoint, this is the logical infer- 
ence, and this fact the following results progressively unfold. 



METHOD OF PROCEDURE. 

In "Technique de Psychologie Experimentale," Toulouse, Vaschide 
and Pieron (1) lay down two methods of procedure: 

"Pour en tamer des recherches personnelles, il y a deux manieres; 

1° Ou bien Ton connait le but a atteindre et Ton cherche dans 
l'experience le confirmation ou la negation du faitadmishypothetique- 
ment et a priori; 

2° Ou bien Ton n'a pas de but precis et Ton enregistre des faits pour 
voir la nature des resultats et se laissant conduire par les faits eux- 
memes. C'est le cas de dire que les faits parleront d'eux-memes." 

Since no investigations utilizing well-known scientific measuring 
instruments have obtained graphic records of all progress of subjects 
on the motor side of the learning process, the second of the above 
methods was here adopted. 

Typewriting and tapping experiments involve arm movements not 
accessible for obtaining graphic records, stop-watches give only crude 
reaction- time, and unless supplemented by extended systematic 
introspection, complete analysis is impossible. Both Swift and Book 
found introspection not always reliable (2) and the latter's method of 
recording progress was so laborious as to make complete records 
impossible. For these and other reasons, the piano-playing instru- 
ment, using only digits of the hand afforded an improved instrument 
for the study of co-ordinated movements. 

Where combined speed and accuracy are assumed to be sufficient 
tests of skill, averages of 25 reactions afforded convenient units for 
showing reduction of reaction-time. The regularity may be studied 
from the mean variations, thus affording a constant check on study 
of the reaction-time. Reduction of errors affords the third and last 
criterion, and these were found to fall naturally into three groups, 
according to the nature of the error. These were designated Duplica- 
tions, Omissions and Out-of-order, which are explained in detail under 
description of the tables. 

(1) Paris, 1904, Chapter 5, p. 227. 

(2) Psychology of Skill, p. 16. 



6 A Study in Practice and Habit. 

In consultation with an expert piano teacher, the possible different 
simple and complex reactions of the five digits were ascertained as 
follows: 

1. Single action of digits, where only one finger at a time is moved. 

2. Double action of digits, in which two and only two fingers were 
moved in succession. 

3. Successive action of digits, where several digits are struck one 
after another in succession. 

4. Concerted action of digits, where they are struck two, three, four 
or five at each reaction. 

5. Complexes of these. 

On the basis of the above analysis, the experiments were outlined 
as follows: 

1. Exp. I refers to single action of digits only. 

2. Exp. II takes up double action of digits. 

3. Experiments III and IV give two different reactions under suc- 
cessive action of digits. 

A time-marker connected with the laboratory clock afforded by 
measurement and comparison a record of the length of the stroke and 
the regularity. For purposes of this experiment arbitrary symbols 
(explained in tables for exp. I) were adopted. During exp. II, only 
the chronoscope was used, giving speed and regularity. In experi- 
ments III and IV, the chronoscope gave the reaction- time, and the 
kymograph recorded the errors. Distraction was reduced to a mini- 
mum by isolation of the subject, which procedure was modified under 
exp. Ill for purposes of comparison. During exp. Ill, calling the 
number of the reaction was signal of beginning the next reaction ; but 
in exp. IV, a telegraph sounder was the only signal. Instruction 
consisted in simple statement to the subject 1. of the object of the 
experiment, 2. to regard accuracy above speed, 3. only to speed with 
growing confidence of accuracy, and 4. what the order of the strokes 
should be. These instructions were easily held in memory, though 
the last two experiments proved harder than expected. 

To operate the piano-playing instrument with the chronoscope, 
a ''primary" key was specially constructed so that the chronoscope 
circuit was made to stay made until the end of the reaction, upon de- 
pression of the key. A second key, the "secondary" key (so-called 
because dependent upon the first for action) was planned upon de- 
pression to break the chronoscope circuit to stay broken until the 
beginning of the next reaction. Hence it is impossible for the reaction 
to begin and to end on the same key. To obtain the above-named 
result, the chronoscope circuit was broken in two places, on the second- 
ary key to stop the experiment, and on the primary key to adjust it for 
the next reaction. An automatic adjustment apparatus, involving 
a third circuit, obtained this result. 



A Study in Practice and Habit. 



tl in 



SSKSfc 



lATiM 



st 



o 



tfl<* i 




T 



S 



til I a 



31 



?ia 



3. 

i 1 



J 










?fO 




8 A Study in Practice and Habit. 

Description of Fig. 1 — A, wood piano key; B, spring cup; C, iron casting; D, slot; 
E, knurled brass screw; F, brass set-screw; G, iron bar screwed to iron casting 
C; H, brass cast-screw; I, brass spring-cup, joined to set-screw; J, spring; K-K, 
rubber insulation; L-L-L, bronze contact spring; M, knurled brass set-screw; N, 
brass plate, screwed to wood; O, hinge; X*-X 2 , binding-posts connecting with marker 
of kymograph. 

Description of Fig. 2. — A, wood piano key; B, spring cup; C, iron casting; D, slot; 
E, knurled brass screw; F, brass set-crew; G, hinge; H, iron bar, screwed to casting; 
I, brass set-screw; J, brass spring-cup, joined to set-screw; K, spring; L-L-L, an L- 
shaped iron bar, screwed to H; M-M, rubber insulation; N-N, Brass plate; O-O, bronze 
contact spring; P-P, soft iron magnet bar; R, knife, joined to P-P, which fits into the 
double bronze lip-spring, Q; S, brass post, set in rubber insulation, T; U, pronged 
brass post, set in rubber insulation, T; V, set-screw socket, of knife-bar, P-P; W-W, 
magnets with soft iron cores; X 1 , binding-post, connected with marker of kymo- 
graph; Y 1 and Y 2 , binding-posts of chronoscope circuit; Z l and Z 2 , binding-posts 
connected with magnets, W-W. 

Description of Fig. 3 — A, B, . . K, L-L-L, same as Fig. 2; M-M insulation; N-N, 
bronze contact spring; 0-0, bronze cup-spring and contact spring; P-P brass plate; 
Q, brass post; V-V-V, a brass L-piece, screwed to Q; S, rubber insulation, set in Q; 
X 1 , binding-post, set in rubber bushing, connecting with X 2 ; Y 1 and Y 2 binding-posts 
of chronoscope circuit; Z 1 and Z 2 , connecting with batteries which operate the magnet 
circuit, and with binding-posts Z 1 and Z 2 of Fig. 2. 

To make this device clear, the diagram and description of the action 
of these keys are here inserted. (See Plate 1, figures II and III. 
Fig. II represents the Primary key, and Fig. Ill, the Secondary key.) 
The action and wiring of these keys is as follows : — When the primary 
key is depressed, spring 0-0 makes the contact with brass plate 
N-N, connected with binding-post X i. X l is connected with binding- 
post X3 in circuit with binding-post X 2, which is connected with 
0-0, completing the kymograph circuit. At the same time, the knife- 
bar P-P is pressed down into the lip-spring, Q, which makes the 
chronoscope circuit. The lip-spring holds the knife-bar in position 
(thus the current stays made), until drawn out by the magnets at the 
end of the experiment. Binding-post Y i is connected with the chrono- 
scope, and the current enters here, goes through lip-spring Q, knife- 
bar P-P, brass post U to binding-post Y 2. Binding-post Y 2 of the 
primary key is permanently wired with binding- post Y 1 of the second- 
ary key. From Y 1 (secondary key) the current passes through the 
contact spring N-N and brass post Q to binding-post Y 2 of the second- 
ary key, the second post of the chronoscope circuit. Thus the circuit 
is made to stay made, and the chronoscope pointer continues to spin 
round until the circuit is broken in some place. This break is made, 
when the secondary key is depressed, by contact spring N-N running 
up on the rubber bushing S in brass post Q, when the dial pointer 
ceases to spin around. 

Upon releasing the secondary key, however, there would be a second 
spin of the pointer, if the current were not broken at the same time 
between knife-bar P-P and lip-spring Q of the primary key, which 
would prevent reading the dial and require a special setting for the 
next reaction. This difficulty is eliminated by the automatic adjust- 
ing apparatus. Z 1 and Z 2 of the primary key constitute a circuit with 
Z 1 and Z 2 of the secondary key, broken at 0-0 on the secondary key, 
in connection with double magnets W-W of the primary key. On 



A Study in Practice and Habit. 9 

depression of the secondary key, contact 0-0 of the springs closes, and 
the current causes the magnets W-W to pull the knife-bar P-P down- 
wards at that end and up out of the lip-spring socket at the other end, 
thus affecting a second break in the chronoscope circuit simultaneous 
with the first. This second break remains so, until the primary key 
is again depressed at the beginning of the next reaction. The kymo- 
graph circuit of the secondary key is effected by wiring bkiding-post 
X2 with Xi, which is set in a rubber bushing and projects through 
V-V as a contact screw meeting 0-0 and out through Z 2, completing 
the circuit. 

Each key of the piano-playing instrument has a corresponding 
marker on the kymograph. Only the primary and secondary keys 
have any connection with the chronoscope. None of the keys have 
any connection with any sounding instrument, hence are dummy 
keys. The other six keys are "simple" reaction keys, connected only 
with markers of the kymograph. The construction and action of the 
simple reaction keys (Fig. I, plate 1) is as follows: The key, upheld 
by the spring J, is fastened to the iron casting C, by the hinge O, and 
brought into line with the other keys by means of the set-screw F. 
In the casting C is the slot D, into which the thumb-screw E screws 
against a flat place on the back of a brass post, projecting up from a 
wooden ridge on the floor of the box. The iron bar G, which is screwed 
to the casting C, holds the set-screw H, thus regulating the excursion 
of the key, as to its depression. The electric contacts are insulated 
from the iron bar G, by the rubber insulation K. The binding-post 
X 1 of Fig. I connects with the bronze contact spring L-L, which, when 
the key is depressed, makes contact with the brass plate N, connected 
with the binding-post X 2, which two binding-posts form the circuit of a 
kymograph marker. Thus the contact spring L-L, completes the 
kymograph circuit, and a depression of the marker is made on the 
drum. The kymograph records the order of movement, and errors of 
order, duplication, or omission. The kymograph is connected with 
all the keys. 

The piano-playing instrument has the appearance of an octave 
on the piano keyboard with the black keys eliminated. Each key is 
enameled white and is of regulation size. The whole is placed in a 
black oak box, 10J^ inches long by 9 inches wide, to which an adjusta- 
ble top S}/2 inches wide is held in place by screws projecting through 
holes in the top and fastened down by brass knurled nuts. The rear 
end of the keys is hidden by this top being raised above them, from 
under which they project to the front of the box. The front of the 
box is likewise adjustable, fastened by two knurled brass-headed 
screws, and with the adjustable top opens up the interior mechanism. 
In the interior, 53^2 inches from the front is situated on the floor of the 
box, a stationary wooden ridge, V/2 inches wide, extending the width 
of the box, and 1 inch high, to which is screwed a %x5-16 brass bar, 
extending the width of the box. In the brass bar are cut 8 seats, 
corresponding to the eight keys, and in each seat is fastened a round 
brass post, 5-16 by lj/g inches, flattened on the back side, fitting into 
the slot in the casting on the back part of each key. Each key is 



10 A Study in Practice and Habit. 

numbered, and by this arrangement they can be interchanged in any 
order desired, yet easily identified. 

On the back of the instrument is a row of eight pair of binding-posts, 

numbered 1, 2, 8, corresponding to the numbers of the several 

keys. The first pair are connected and permanently wired with X 2 and 
X 3 of the primary key and the last pair with X 2 and Z 2 of the secondary 
key. The other six are permanently wired with X 1 and X 2 of the other 
six keys of the corresponding number. These circuits operate markers 
of the kymograph. Above this row are two pair of binding-posts, 
one pair of which stamped O is connected with Y 1 of the primary key 
and Y 2 of the secondary key, and permanently wired with them. The 
other pair are blank and are permanently wired with Z 2 of the primary 
key and Z 1 of the secondary key. The 20 binding-posts connect by 
temporary wires to a like series on the wall. Eight pair connect with 
cells and markers of the kymograph corresponding. The pair marked 
O connect with the permanent wiring system of the chronoscope, com- 
pleting the circuit. The blank pair with cells constitute the adjusting 
circuit. 

Subjects. Four subjects reacted throughout the four experiments. 
Mr. Hitchcock is a graduate student, who plays simple pieces, popular 
music, and the like. Mr. Fernberger once had lessons for a few weeks, 
then dropped them, but does not play the piano. Neither Mr. Young 
nor Miss Mason know anything at all about playing the piano. The 
three latter are graduate students with considerable training in labora- 
tory work and in introspection. These differences are manifest in the 
nature of the results, and partly explain the relative quickness of the 
reduction of errors and reaction-time. The subjects were instructed 
to regard accuracy primarily, but to develop speed as fast as they felt 
able to do so, and if they overspeeded, to adopt a slower rate. Each 
was left to his own initiative in the method of learning, and was con- 
sistently acquainted with his progress. Whenever a decided break 
in the averages occurred from time to time, the experimenter sought 
by questions to elicit introspections from the subjects, and thus supple- 
ment his own explanations. These more often than not agreed with 
his own, but not always. No elaborate introspective program, such 
as Book used (p. 16), was arranged, and although this might have 
supplied additional information, after a study of the tables, I am con- 
vinced that the instrument records all occurring changes. A too 
complex introspective scheme is liable to distract the attention of the 
subject to himself and from his work. He was instructed to give his 
whole attention to the practice. 

The physical condition of the subjects and the influence of weather 
conditions was noted, (especially one day when the room was cold, 
the rate was affected). Emotional conditions did not seem to play 
any considerable part. In general, the attitude in the working periods 
was that of busy concentration, but during periods of relaxation, work 
was for the moment forgotten. Contrary to expectations, consider- 
able interest developed on the part of the subjects, as the experiments 
progressed. The knowledge of results seemed to relieve the ennui, 
which ordinarily attends practice. A sort of group spirit and pride of 



A Study in Practice and Habit. 11 

attainment arose among several workers, especially in handling the 
instruments. In fact, many helpful suggestions came from members 
of the group. Subjects "F" and "M" were liable to overspeed and to 
have "off" days. Subject "Y" was troubled with nervousness, and 
at the end of the third experiment (first part) often became confused 
and discouraged. Several subjects showed the tendency to crowd 
themselves into a "breakdown stage," as Book noted in his experi- 
ments. Considerable pleasure was exhibited whenever a "better 
way" was found for making a complex reaction. Four other subjects 
were introduced in experiment I for purposes of comparison, whose 
results are given in the general summary only. One day in experiment 
I, subjects were told to speed and disregard metronome time. 



EXPERIMENT I. SINGLE ACTION OF DIGITS. 

Conditions of experiment. The subject was seated on a piano stool 
with the keys at the regulation height of a piano keyboard. The 
subject was isolated. The subject placed the five digits down on the 
keyboard, depressing the keys, then raised the thumb, making 20 
consecutive down strokes. After 20 strokes, the thumb was again 
held down with the other digits, the forefinger raised, and 20 reactions 
thus taken ; and so on with the other three digits in the same manner. 
This completed 100 reactions at each sitting. The non-reacting digits 
were held down all the time that each digit was reacting, and involun- 
tarily raising one digit was counted an error. The subject was in- 
structed to make the down strokes in metronome time, one stroke 
per second. The down stroke and the up stroke were to occupy the 
same time, i. e., one-half each, constituting the "length of the stroke." 
The regularity was figured by comparing 20 down strokes. In order 
to gain some idea of the metronome time, the subjects were allowed 
20 preliminary practice strokes with the metronome beating. After- 
wards, the metronome was taken away, and not presented any more 
while they were reacting although they were allowed to hear the 
metronome beat between experiments, provided they did no tapping. 

Five keys were connected with five markers of the kymograph, and 
a sixth marker with the laboratory clock. When the subject depressed 
the five keys, the five markers were depressed simultaneously with 
them, and then as the first digit was raised, the experiment began when 
the first digit was depressed again, making a mark at each depression 
of the reacting digit. If a non-reacting digit was involuntarily raised, 
the marker recorded the error. The time or rate was measured by 
erecting perpendiculars from the line of the time marker to the be- 
ginning and the end of the strokes of the first and the last reactions, 
and counting the seconds for the 20 reactions. The length of the 
strokes was figured from the observed average of the strokes, and 
measured by means of the perpendiculars from the line of the time- 
marker. The regularity was reckoned by comparing the length of the 
strokes, since the speed of the kymograph was regulated to 



12 A Study in Practice and Habit. 

make the deviations easily observable. The groups of 20 reactions 
were adopted, because fatigue materially modified the conditions of 
practice. The tables give the errors, the length of the average of the 
strokes, the average regularity, and the rate in seconds for groups of 
20 reactions with the order of the series. The length of the strokes 
and the regularity are given by means of arbitrary symbols, explained 
in the tables. The errors are given in detail for each non-reacting 
digit. The first table in the summary gives the reaction results for 
all the subjects, as far as they go; the second table for four subjects 
who attended regularly at least twice a week. The third table gives 
a total of errors during the reaction of each digit for each non-reacting 
digit, of ail the subjects. Where blanks occur in the tables, conditions 
of records were such as to make a report impossible. 
The results are reckoned in the following tables : 

TABULATION of EXPERIMENT I. 

Single action of digits, regarding errors, regularity, and the length of the down 
stroke. Under regularity, "A" means nearly perfect; "B" means good (not more 
than 2 breaks); "C" not so good (more than 2 breaks); "D" very bad, practically 
a break down. Under length of stroke, "X" is more than ^ second on down stroke; 
"Y" is }/% second (approximately) ; "Z" less than K second. Groups of 20 reactions, 
The rate shows the number of seconds to make 1 group of 20 reactions. Under errors, 
the number in parenthesis shows on which digit the error occurs. 



A Study in Practice and Habit. 



13 



© 

o 
co 



«*£ 



o 

00 
CM 



o 

CO 
CM 



>>c3 



CM 



O 
CM 



© 



O 
O 
CM 



*0 



N e8. 



NC3 ^ 



s, o3^; 



>>o3 



Oi 



N e3' 






Kl c3 



N 03^ 



»«s 



o 

00 



>j03 



>»o3 



n s3_; 



N 03 



OS 



o 
co 



X 03 



X 03 



««S 



S3 03 



os 



O 

o 

Q 

o 

O 

P3 



o 



o 

CM 



O 

o 



o 

oo 



o 

CO 



O 



o 

CM 



.2 

°+3 
u 
03 
CD 



O 



o 

# CD 
IS* 

gq 



^c3^ 



iO 



>> o3 



CM 



«s 



>*0 



^03^ 



NX 



C5<M 

CO 



co 



u 

bC CD o3 S 



11 t-l ■ 
2 p- 



>< 



5>> 03 



J»o3^ 



>> 03 



X 03^' 
<M 



N 03 



>>o3» 



>> o3 



CM 



>>o3: 



N c3g^ 



>jo3 



N c3 



© 



KJ c3 



Xo3^S 
CM CO 






"II *-■ 



be © o3 e 



>i03 



CO 



be <y o3 ^ 






««sS 



>> 03 



a 



>>*<% 



CO 



>,03^ 



^2- 



X o3 



KJ c3 



00 



Ttl »0 



bC O o3 S 




14 



A Study in Practice and Habit. 



o 
o 



o 
oo 



N«S 



05 



*«3 



© 



X c3 



O 



o 



«*£ 



*«% 



>,C32 






NC3^ 






<M 



O 
00 






>.o3 



is s3 



oo 



>> o3^ 



««5 



n c3~ 



N cSOV 



iO 



o 

CO 



X o3 



X 03 



«0 

(M 



« *3 



« oSOV 



CO 



O 



>>«8 






««s 



s s3 v5 



O 



O 

o 



>>o3® 



««5 



M 03 



>>o3 



n 03^; 



>>c3 



M 



**2 



**2^ 



o 



O 



O 



o 

00 



o 

CO 



o 



N 03 



« «2 



N032 



(M 



>^8 



•O 



n a 



<N 



>>c3 



N «2 



M 03 



CO 



« =3 oo' 






CO 



>»o 



<n 



o 



00 

G 
O 

o 
03 



o 
55 



.O. 
=5 
GO 



"S 



fcfi <U 03 S 



> 



*«& 



W2 I oj |: 

bfi £> =3 C 



X 



io 

>» c3 fQ 



CO . w 5 



Uh 



«^« 



• *>♦» 2 

bo o o3 E 




A Study in Practice and Habit. 



15 



CO 



o 

00 



NOJJS 



>>«22 



o 



»o 



X e3 



<N 



O 



O 



O 

o 



M C3^ 



^CJ^ 



« *£ 



NCJ^ 



>>^2 



NCJ^ 



««2 



««2 



«*-8 



o 

00 






>>c3 



M 03^ 



N c3 



00 



o 
<o 



"5" 



>> 03^, 



X 03 



CO ^~^ 



si 89 o 



sa c3 



© 



>>c3 






>»o3 



<N 



N 03 






N 0300 



© 



>*o2 



K e3 



>» 03^ 



N CJ 






W 

H 
H 

o 



o 



© 
© 



>>c3 



05 



>»o3 



>>^^- 



*^S 



© 
00 



© 
© 



*^ 



^,03^ 



n 03^; 



>jz 2-- 



>>o3© 



N03S 



© 



«-QS 



N^S 



© 



>>«% 



<M 



X 03 






N 032^ 



«o 



<M 



W ' 



© 



30 

o 

03 

o> 



£ 



N "°«0 



bC a> cJ £ 






>>03S- 



-M ' OS 



bfl » «8 S 



e 5 



rn 



rH v — s -' 



03 

5C <» 05 S 



02 



>- 



N-i-H 



1 T | 




16 



A Study in Practice and Habit. 



CO 



N c3^ 



O 
00 



>>*2 



o 
co 



K> 



X 03, 



<N 



O 









N 03' 



o 



K 03 



WW 






iC 



N o3 



o 
o 



N«2 



>,032 



SI o3^ 



O 

00 



o 

CO 






>>*<£ 



>>038 



X o3 



*C 



N 03, 



« *2 



N 03 OS 



K 03 



00 



o 



>j o3 (^ 



>>o3 



<N 



"^ 



lO 



NX! 



o 



>>*2 



X c3 



NoS^ 



N o3^ 



O 

H 

o 

Q 
O 

H 
O 
<! 
W 



o 
o 



>>°3^ 






^2- 



nx^ 



o 

00 



>>°s 



*«8 



*«2$£ 



NX^ 



o 

co 



iO 



l-ICM 



r* b- CO 



>>*§ 



N 03 J2 



i~ 



N 03 



C0»O 



rH C<l i— I 



o 



00 



>>o£ 



XX 



CO 



^C 



O 



t-H(M 



NX 



CO 



O 



« o^ 



X 03 






>> o 



OON 






'43 
o 

03 
CD 



o 






og 

o3 C 



. tJD 



£ c 






i- 

CO 



x 

bc-2 B' 

C ~ s_ 



bC - « „ 



GO 



tu « 



&0-*f S 



c3 C 



^p^h 



o 
X 
GO 



* 



DC 



Uh 




A Study in Practice and Habit. 



17 



o 
o 



tO 



O 
00 
<M 



>>*<* 



O 

co 



O 
CM 



O 
<M 
CM 



o 
© 

CM 



o 

00 



X o3 



CM 



N 03 



CM 



>>o3 



OS 



n o3: 



nj o3 



CM 



>> ce 






(S3 03 



Tfl 



>,03© 



N 03 



O 



^^(M 



X 03 



to 



N o3 



n c3 OS 



CO 

CO 



o 

CO 



o 



O 
CM 



O 

o 






X o3 



tO 



N 03 






>>o3 



N c3 



CM 



to 

^ ^OS 



J>>o3 



OS 
CM 



CM 



>>c3 



os:* 



X o3 



>>-Q 



N 03 



to 

00 



N 03 00 



CO'* 



si 03^ 



to 



H 

o 

»— 1 

Q 
O 

H-l 

H 
O 

<! 



o 

00 



o 



iO 



^03 



tP 



to 
<M 



tsa o3 



CM 



>>o3 



iO 

OS 



X 03 



oo 



CM 



N o3 



iO 



X o3 



tO 



KJ 03 



tO 

CO 



© 






X 03 



>>o3 



OS 



X o3 



1> CO 
1—1 v -~' 

CO 



c 

CM 



K! 03 



IO —'-N 

co Vw '' v -' 



to 



X 03 



>so3 



1> CM CO 



CM 



S3 *C 



!>. CO ^ 
CM tF 



,0 

c3 
cp 



O 



-O. 
CO 



^ : © §- 

bfi CD o3 S 



© o- 



CO 
bO © <3 C 



CO . <» g. 
bfi © o3 C 





■OBBSBRKS 



bfi CU e3 G 




18 



A Study in Practice and Habit. 



o 
o 



co 



03 



o 

00 



CO 



CO 



p 

CO 



■i 

+3 



(1 

03 

a 

13 

a 

o3 



2 



S 



O 



oo 



o 



00 



o 



00 



o 

c3 
o 

6 



CO 

d 



CO 

o 

pq 

P 

CO 

P4 
P 
O 

o 

CO 

O 

PS 

w 
o 

«i 

H 

W 

Eh 
W 

Cm 

o 
o 



o 



o 



O 

o 



O 

00 



o 

Q0 



o 



o 



o 
oo 



o 
co 



o 



o 



CO 



CO 



CO 



«* 



T* 



-* 



TP 



Tt< 



00 



00 



00 



CO 



<* 



T* 



^ 



00 

G 

4 o 

C3 

o3 
03 

P4 



•jO 
CO 

6 

5 



o 

CO 









13 
o3 

-a 

0£: 



o 



<N 



<N 



<N i-i 



^ 



tH 



r^i 



M< 



r2 

CO 

6 



co 



lO 



<N 



a 



o 
Eh 



o 



PI 
O 

+^" 

'So 
-9 



I 

03 
o 

a 

o 



3C 

'-a . 
c fee 



O tX 



fl.S 
o S 

C3 13 

o3 



13 
03 

B 

2 
2 

03 

03 

09 

^3 



* 



o3 






6h 

-J3 PQ 



§s 



G O 

O f 

— i 03 

f * 



a> 


* <u 


03 


03 


03 




> 


<N 


CO 


t> 




fe 


CO 


W 


o 


03 












i— < 










(N 


• 1-4 


*- 


« 


CO 


Tf 


1-H 


Q 


13 


13 


13 


13 




(* 


* 03 


.03 


03 


03 




3 
O 


00 
CO 


o 


CO 




fe 










03 










oO 


••h 


l-H 


<M 


CO 


lO 


CO 


n 


T3 


w 


13 


13 




0) 

hi 


* 03 

to 

CO 


03 


03 

CO 


03 

rH 




H 










03 












b£ 


)— 1 


(N 


■^ 


»o 


t^. 


Q 


-o 


13 


~o 


w 




o 


03 


03 


03 


03 




< fc 




i-H 


o 


1—4 




H 










03 












OJ 


bfi 

• *■* 


— 


CO 


r»< 


»o 


CO 


q 


13 


13 


XJ 


13 




03 

o 


OS 
CO 


03 


03 
Ci 
CO 


03 


03 












Ot 


bO 










00 




o* 


CO 


•** 


»o 




4 


13 


13 


T) 





v 

c3 



A Study in Practice and Habit. 19 



ANALYSIS OF RESULTS. 

1. Analysis of Errors. 

Errors occur in groups, usually not on several digits, but on one. 
M. is predisposed to errors on digit 5, even in later more complex ex- 
periments. F. experiences difficulty with digit 2, though not in groups 
in the same series, but in differing series. This fact constitutes an ex- 
ception. The same errors also tend to reappear during subsequent 
practices, especially on the same day. Some errors become so firmly 
established that they recur even at later stages of practice, as M. on 
digits 2 and 5.* In other words, unless special attention is given to 
correcting each error, when it first occurs, each recurrence is a special 
practice of that error. Subjects were informed of their errors, there- 
fore, during the entire series of experiments. In experiments on habit 
subjects should be informed of their results, if corrections and formation 
of a given habit are desired. In some cases errors will be eliminated 
without special attention being given to them, but as frequently re- 
currence of the error will so exaggerate the tendency to reproduce it 
that it requires special practice almost equal to relearning to eliminate 
the error. Piano teachers give this fact special attention, for when an 
error occurs, the pupil is made to stop his general practice to obtain 
the particular correct response. 

Errors fall into two general classes, accidental, due to perceptional 
difficulties, and structural, due to anatomical structure of the function- 
ing organ. Under this latter head may be subsumed oscillations of 
the thumb. On the whole, the initial multiplicity of errors is due to 
local difficulties, such as unfamiliarity with the keyboard, nervousness 
in approaching a new and difficult situation, association of a particu- 
lar stimulus with a particular response, general mental confusion at 
the novelty, the attention untrained to watch for particular errors, 
lack of concentration, and so on. Such errors are rapidly eliminated 
by practice (see tables 1 and 2 of the summary) . Even in later periods 
many errors are due to local conditions, distraction, fatigue and re- 
laxation of effort, e. g., M., digit 2, series 160, 180. Great care was 
taken to eliminate such causes of errors, and in some cases unavoidable 
interruptions materially modified the results. These three causes 
should be eliminated if possible, having no bearing on the physiological 
effects of repetition and response. In general, the rapid reduction 
of errors in the first few practices consists of those of accident, due to 
local conditions and mental confusion in meeting a new situation, 
which are rapidly eliminated without special attention. The few 
errors of H. and F. throughout are explained by their disregarding 
instructions to bend the middle joint of each digit at right angles, 
and to their previous training and general familiarity with the piano 

* Johnson says (practice and habit, p. 82), "Practice does not always mean an ab- 
solute gain in efficiency; it may produce negative results." Swift and Schuyler 
(the Learning Process, p. 310) remark, "In the curve of errors that which attracts 
attention is the remarkable persistence and regularity of mistakes." Book (pp. 140 
fl.) also notes the disastrous effect of the "practice of error" in the "critical stages." 
For discussion in the more complex reaction, compare p.44, under exp. III. 



20 A Study in Practice and Habit. 

keyboard. (Bending the digits at the middle joint made the reac- 
tions much harder than to lay them flat upon the keys.) 

The second and more important source of errors is anatomical 
structure. This fact of structural modification is especially clear in 
exp. I, and can be traced in the error column, of which we note: 
In reaction of digit 1, tendency to raise digits 2 and 4. 

" " 2, " " " " 1,3, and 4. 

u „ 3> <i « u u 2 and 4< 

11 " 4, " " M " 2 and 3. 

" " 5, " " n " 3 and predominantly 4. 

In special cases of Y., He., and Ber., the oscillations of the thumb 
during the reaction of digits 3, 4 and 5. 

Errors made on the same day are sometimes eliminated, and do not 
recur. 

Errors during the first part occur even at advanced stages, and give 
evidence of being unconsciously practiced. 

Digit 4 is the greatest offender in the error column. 

Digits 2 and 3 show relatively the same number of errors; and digit 
5 shows the smallest total of all. The totals of errors are: Digit 1, 
116 errors; digit 2, 64 errors; digit 3, 63 errors; digit 4, 142 errors; 
digit 5, 27 errors. 

In summary, table 2, after a rapid reduction to a minimum, there 
is a corresponding rise and temporary level of errors considerably above 
the previous minimum. These are errors of structure, presenting 
special difficulty. F. found difficulty with digit 2, and M. shows 
practice of errors during reactions of digits 2 and 5. 

As a rule the thumb of the hand acts independently of the fingers, 
and in habits of life, the four fingers act together, not separately. These 
habitual actions due to anatomical structure are phylogenetic in their 
origin, hence, are deeper rooted than any other kind of interference. 
Where independent action of these digits is demanded, therefore, 
special training is required, since when one digit acts separately, the 
new habit interferes with the old phylogenetic habits, which must be 
overcome. When customary habits break over control acquired by 
severe effort in the new habit-formation, an error occurs in raising 
out of due time one of the non-reacting digits. This is the immediate 
cause of a large class of errors of proximity. 

Digit 4 shows the largest total of errors for every subject, and pre- 
sents a special physiological difficulty. If the palm of the hand is 
held upright, and the third digit is bent at right angles from the palm 
at the joint with the palm (carpo-metacarpal), the fourth digit will, 
for most persons, be drawn down with the same while digits 2 and 5 
remain perpendicular. This is also true when digit 5 is bent down. 
This peculiarity is caused by the close interconnection of the ligaments 
especially on the dorsal side of the hand, at the carpo-metacarpal 
joints,* and particularly the relation of the tendons, f which control 
the action of the digits. The thumb is severed from the action of the 
other digits, not merely by position, but primarily because of the 

*See Human Anatomy, Sobatto, ed. by McMurrich, p. 124. 
fSee Human Anatomy, Sobatto, ed. by McMurrich, p. 198. 



A Study in Practice and Habit. 21 

joining of the tendons with the forearm muscles far back in the wrist. 
The tendons of the thumb act with those of the palm, not those of 
the fingers. Again, digit 2 is relatively independent of the others in 
the action of the tendons on the dorsal side, though connected with 
digit 3 by a special tendon, which, however, is situated farther down 
in the carpus than the other interconnecting tendons. The connecting 
ligaments between digits 3-4-5 are much more complex and immediate 
than those between digits 2 and 3. Digit 4 is so closely related to 
digits 3 and 5 that the slightest extension of the latter two tends to 
raise digit 4 with them. The tendon which governs the 4th digit di- 
vides in the carpus below the joint, on one side immediately connecting 
with digit 3 and on the other with digit 5. It joins again between the 
carpal and middle joints of the digit. From the foregoing observa- 
tions and facts of anatomy, the close interrelation of digits 3-4-5 pre- 
sent special difficulty for the control processes in the nerve centers to 
preserve a distinction in responses against long established phylo- 
genetic habits. The flexing tendons which control these reactions do 
not act separately, but develop a unity of response. Here anatomy 
presents a real case of interference by phylogenetic habits with the new 
series of responses, and these difficulties can only be overcome by spe- 
cial attention to the particular response, thus gradually eliminating 
errors by practice, and establishing stronger new habits of response. 
Unless constantly corrected, the wrong response is practiced instead 
of the right one. Sometimes special errors did not recur again, but 
certain errors often repeated tended to recur even in the later stages 
of the experiment, exhibiting a specific practicing of the errors. Er- 
rors from structural causes or from old habits therefore present spe- 
cial difficulty, and subjects in every instance should be acquainted 
with the kind of mistakes made, if not with their progress in general. 
In Practice Without Knowledge of Results, Judd* shows the di- 
vergence between habits acquired with and without knowledge of re- 
sults. Habits unconsciously acquired are distinguished from those in 
which there is no knowledge of results, as the former are not conscious- 
ly controlled; but he recognizes a third class in which each detail is 
corrected by attention to the fault. Attention alone secures active 
control in the acquisition of the habit, and only this latter kind of con- 
sciousness gives perfect control. This fact is demonstrated in diver- 
gent ways by the errors on digits 1 and 5. The muscularly weak 5 th 
digit is held very rigidly on the board, calling forth greater effort and 
attention, hence the few errors which do occur are those of proximity 
to digits 3 and 4. The oscillations of the thumb, however, present 
the reverse condition from that of proximity. Table 3 of the summary 
shows above 100 errors of the total 412 made by 3 subjects during re- 
actions of digits 3, 4 and 5. That other subjects were not so troubled 
presents an interesting condition. The experimenter, being one of 
the subjects so troubled, after directing attention specifically to this 
difficulty, finally found the explanation of the fact by the aid of in- 
trospection. Until attention was called to these errors, no subjects 
were able to introspect them, and this fact strengthens the solution 
given. When the last three digits are reacting, attention is diverted 

♦Yale Psychological Lab. Studies, N. S., I, No. 1, pp. 196-199, Cp. p. 185. 



22 A Study in Practice and Habit. 

almost wholly away from the thumb, on account of its isolated posi- 
tion from the other digits. There follows a corresponding relaxation 
of effort in depressing the thumb. When any digit is in motion, there 
is always a strong tendency for other digits to move also, and in such 
subjects the oscillations of the thumb arise. Some subjects direct the 
attention to a smaller area in the expenditure of effort than others, 
and always in the direction of the moving member.* The diversion 
of attention toward the member in motion, and away from the non- 
reacting digits, thus causes a relaxation of effort on the non-reacting 
members, and an error is more liable to occur. One is tempted to 
state the principle, that where there is motion, there is effort, and the 
place of maximum effort is the focal point of attention. 

2. Analysis of the time element. 

As stated in the preliminary explanations to this experiment, the 
Rate includes the time in seconds that it requires to make a series of 
twenty reactions of a single digit. In the system of symbols, re- 
garding the average length of the stroke, X is more than 3^2 second, Y 
is y<i second, and Z less than Y2 second. The length of the upper 
pause is not always the same as that of the lower pause. All measure- 
ments were made of the lower pause only, since the reaction begins with 
the down stroke and ends with the up stroke. Examination of the 
tables will show that in many cases the down stroke length is Y, when 
the rate is 25 seconds or more. The condition named above, there- 
fore, means that the up pause was longer than Y2 second, while the 
down pause was made in metronome time, the reaction being ideally 
half and half. Some subjects made a decided pause between reac- 
tions. Again, some down pauses were quite sharp and quick, but be- 
cause the up pause was considerable, the rate approached nearly the 
true metronome time of 20 seconds. Such a case would be reported 
Z. In the case of H., a series reported Z has a rate of 22 seconds, thus 
denoting such a sharp, down stroke, but a considerable pause between 
reactions. The pause between reactions has for purposes of our ex- 
periment no significance. 

The series of H. is remarkable for regularity, except on the 2d digit. 
The same is true of F., save the 4th digit. Each subject had enough 
preliminary practice to give them a fair regularity of response in con- 
trol of the individual digits, but control was by no means equal for all 
the digits. Regularity is an accurate test of which are the best con- 
trolled digits. Y. and M., on the other hand, show progress in regu- 

*The focal point of attention and its distribution over various areas does not call 
for discussion here. It is of vital significance, however, as the studies of illusion 
show. (Cp. Yale Studies, N. S., I, No. 1). Davis in Cross-education (Yale Studies, 
VI, 1898, p. 50) notes that "In the tapping tests close attention and a strong wi.ll 
power were hindrances." MacMillan (see rev.) notes that the meeting of the end 
in view in every case affords the stimulus for adjustment, and the "control of the 
habit in its formation and use comes from the end set up." Coover and Angell (Am. 
Journ. Pey., XVIII, 1907, p. 328) assert the factor of "an equitable distribution of 
attention to the various possible reactions so as to be prepared for all, as one influence 
of practice in one series on another. Bair (Practice Curve, p. 41) states that atten- 
tion is controlled wholly by our habitual bodily adjustments. 



A Study in Practice and Habit. 23 

larity, and the utility of this kind of practice by piano pupils, where 
time is most important, but hardest to acquire. 

The most remarkable fact in the study of regularity is the entire ab- 
sence of rhythm, which was expected to creep in. While listening to 
the metronome beats, subjects can detect a decided rhythm in the 
sounding beats. In this case, no such instructions were given, since 
regularity and not rhythm was desired. But H., who plays pieces where 
rhythm (melody) constitutes the effective part of the tune, shows no 
such tendency. Rhythm of movement is not part of the time series 
in single action of digits, but in more complex processes, a different 
condition prevails.* 

Estimation of time differs consistently in the cases of each subject, 
and here the so-called "personal equation" enters to a decided degree. 
H. overestimates, especially on the up pauses, and as he was absent 
(series 200-240) when the subjects were instructed to speed, he at no 
time attempted to speed, though he was told that he overestimated. 
F. underestimates time, although there were occasions where he was 
instructed to speed, as already noted. However, his reaction-time 
was considerably quicker than that of the metronome time. Practice 
in his case, instead of slowly approximating the metronome time, 
seemed to gain speed for the whole series, and remains consistently Z 
throughout the latter part of his reactions. M. also exceeds the speed 
of the metronome time toward the latter part of her experiment. Y., 
on the other hand, evidences no certain regularity, but the rate for 
both H. and Y. slowly approaches the metronome time of 20 seconds. 
M. gains speed on digits 4 and 5, exhibiting fatigue. The other four 
subjects on the whole approached the metronome time, but the number 
of practices was too small to draw inferences, and they show the same 
iregularity. F. and M. were too fast, H. was slow, and Y. irregular in 
the more extended series. 

Practice tends to regularity of response, since in each case the ir- 
regular responses rapidly became regular. Regularity is therefore one 
criterion of the contributing factors of adjustment to control. The 
initial irregularities have the same causes as the errors of Accident, and 
follow the same law of decrease. The psychic antecedents are eventu- 
ally the same, as well as the objective conditions which cause them. 
They show the corresponding rapid decline with practice. 

The Rate depends upon the length of the up and down pause, and 
shows a slow decrease in slow reactions toward metronome time ; but 
the tendency is for the quicker reactions to become accelerated. The 
general tendency in time estimate is toward shortening the time in- 
terval. Variations arise in cases, where subjects listened to the metro- 
nome between experiments, thus gathering new associations. They 
would all have steadily increased speed, if left unguided by new sen- 
sory associations. The length of the stroke is therefore dependent 
upon perceptional time associations, f Time estimation is therefore 
shown to be of central origin, and concerns processes of association. t 

*See p. 41; also p. 44; also p. 37. 
fCp. Raif, p. 357. 

JCp. Johnson, ibid., p. 102, where he notes, "There is no 'indifference point' 
from which the subject does not vary with long continued practice." 



24 A Study in Practice and Habit. 

This fact has no connection with the reaction-time of experiments III 
and IV., as they do not involve time estimation. 

The foregoing analysis of tapping experiments shows that even the 
simplest reactions of a single digit involve complex processes of co- 
ordination. The chief difficulties are those of interference of old 
(phylogenetic) habits and anatomical structure, objective conditions 
connected with mental confusion, and narrowing the field of atten- 
tion to only part of the situation. Of these, the rapid improvement 
is assignable to clearing away of the objective difficulties; but the 
eliminating of interference of old habits of response and anatomical 
structure involves a long, laborious period of practice. The effect of 
this experiment is a preparation for the more complex reactions to 
follow. 

EXPERIMENT II.— DOUBLE ACTION OF DIGITS. 

Subjects: Four subjects reacted in this and succeeding experiments. 
These subjects were H., F., Y., and M. of the first series. H., F. and 
Y. attended practice 3 times a week and M. twice. H. and Y. prac- 
ticed all possible reactions for double action of digits. 100 of each sort; 
F. and M. practiced 500 reactions, specially preparing them for the 
i -5-3-2-4 experiment to follow. 

Conditions of Experiment. No errors occurred, hence the kymo- 
graph was discontinued. The primary and secondary keys were 
shifted to the desired places and the chronoscope gave the reaction- 
time and the mean variation as the sole criteria of progress. This ex- 
periment was introduced at this stage, partly to investigate the double 
action of digits themselves, but chiefly for the comparative influence 
of special training and general training on a complex reaction. The 
signal for each new reaction was the calling of the numbers, and the 
subject was instructed to use only the sound of the voice as the signal. 

The tabulation of the results is as follows: 



TABULATION OF DOUBLE ACTION OF DIGITS IN ALL POSSIBLE 

COMBINATIONS. 
Averages and Mean Variations for Groups of 25 Reactions. 


Subj. Y. 


Subj. H. 


Subj. Y. 


Subj. H. 


Subj. Y. 


Subj. H. 


Ave. M. V. 


Ave. 


M.V. 


Ave. 


M.V. 


Ave. 


M.V. 


Ave. 


: M. V. 


Ave. 


M. V. 


DIGITS 1-2 


DIGITS 2-1 


DIGITS 3-1 


256 
115 
230 
224 


25.0 

5.8 

12.6 

21.4 


164 
160 
271 
146 


12.3 
9.4 

21.5 
9.8 


144 

145 

108 

69 


6.6 

17.7 
35.7 
29.5 


101 

100 

102 

99 


2.9 
2.5 
4.6 
3.5 


73 
44 
54 
21 


43.1 
23.5 
13.3 

8.4 


147 
132 
150 
150 


8.7 
10.4 
11.8 

9.5 


DIGITS 1-3 


DIGITS 2-3 


DIGITS 3-2 


193 
198 
152 
133 


11.9 
15.2 
24.0 
37.4 


220 
220 
205 
200 


9.6 
7.9 
8.9 
5.7 


199 
96 
43 
49 


16.0 
46.0 
13.5 
19.6 


106 
101 
101 
107 


4.9 
2.0 

2.8 
6.4 


45 
32 
41 
20 


22.4 

8.7 

13.3 

12.2 


163 
166 
161 
162 


6.6 
9.1 
6.0 
7.3 


DIGITS 1-4 


DIGITS 2-4 


DIGITS 3-4 


259 
230 
190 
174 


18.6 
23.8 
17.3 
14.3 


105 
101 
102 
101 


5.0 
7.3 

5.9 
5.9 


227 
212 
175 
155 


15.2 

9.0 

16.1 

11.3 


194 
191 
195 
196 


11.6 

9.0 

13.6 

14.9 


75 
43 
49 
49 


41.7 
19.8 
24.6 
22.1 


86 
88 
88 
93 


3.7 
3.5 
3.5 

2.8 


DIGITS 1-5 


DIGITS 2-5 


DIGITS 3-5 


198 
205 
187 
184 


10.0 
19.7 
12.8 
11.6 


168 
148 
151 
206 


9.2 

6.2 

13.9 

73.5 


179 
173 
155 
153 


17.6 
19.4 
10.4 
14.0 


194 
191 
184 

184 


6.4 

9.1 

8.0 

13.1 


167 
120 
108 

85 


52.0 
29.5 
17.2 
16.4 


190 
192 
198 
201 


7.8 
6.8 
6.2 

7.7 


DIGITS 4-1 


DIGITS 4-5 


DIGITS 5-3 


96 
39 
26 
36 


33.2 

13.8 

7.0 

9.9 


195 
195 
196 
199 


11.1 
3.3 
7.1 
9.0 


129 
93 

72 
84 


44.1 

, 24.6 

22.1 

24.0 


192 
190 
199 
195 


8.7 

8.9 

12.2 

9.1 


95 
63 
27 
23 


25.1 
21.1 
13.8 

8.8 


74 
75 
72 
73 


11.3 
10.2 

7.2 
7.2 


DIGITS 4-2 


DIGITS 5-1 


DIGITS 5-4 


90 
54 
28 
32 


42.0 
17.4 
10.0 
14.0 


97 
70 
75 

85 


43.0 
14.4 
18.3 
14.4 


149 

137 

66 

60 


25.0 
32.4 
13.8 
12.2 


198 
199 
200 
200 


8.6 

10.9 

8.5 

7.5 


38 
46 
57 
44 


13.1 
21.2 
19.6 
12.3 


76 
79 

83 
82 


18.4 
12.7 
14.1 
14.4 


DIGITS 4-3 


DIGITS 5-2 




38 
33 
23 
26 


13.0 

11.8 

9.2 

10.7 « 

i 


94 
80 

86 
78 


11.6 
15.2 
20.5 
19.9 


120 
70 

48 
52 


38.7 

19.1 

9.8 

17.5 


89 

82 
69 
82 


8.5 
19.4 

9.9 
10.9 











26 



A Study in Practice and Habit. 



DIGITS 1-5 


DIGITS 3-2 


Subj 


.F 


Subj. 


M 


Subj 


.F 


Subj 


.M 


Ave. 


M. V. 


Ave. 


M. V. 


Ave. 


M. V. 


Ave. 


M. V. 


156 


9.8 


154 


30.4 


73 


14.6 


131 


24.3 


146 


13.5 


135 


23.5 


71 


15.8 


78 


12.1 


142 


9.7 


138 


23.4 


72 


16.4 


80 


12.9 


132 


19.8 


131 


11.8 


58 


18.8 


78 


15.9 


146 


20.8 


212 


29.6 


64 


15.0 


81 


15.6 


175 


19.6 


125 


33.6 


60 


14.2 


72 


15.7 


136 


32.8 


68 


15.5 


45 


15.4 


78 


13.3 


72 


4.3 


65 


6.5 


50 


11.7 


75 


15.7 


121 


16.5 


64 


4.9 


40 


10.8 


71 


18.3 


124 


21.9 


69 


6.0 


52 


18.4 


80 


12.9 


140 


18.2 


77 


5.0 


86 


13.3 


78 


13.0 


93 


25.8 


69 


7.7 


90 


18.3 


73 


15.2 


164 


13.8 


130 


11.4 


62 


13.4 


73 


16.3 


161 


7.6 


128 


38.2 


58 


11.8 


56 


15.6 


140 


18.1 


52 


8.8 


63 


15.6 


61 


12.6 


151 


21.6 


76 


10.2 


87 


18.0 


66 


15.9 


89 


9.9 


143 


20.4 


54 


16.2 


67 


15.7 


90 


7.3 


185 


30.1 


65 


12.4 


71 


18.5 


82 


7.4 


229 


21.7 


69 


9.2 


61 


14.0 


91 


7.2 


163 


25.8 


61 


11.2 


56 


14.8 


DIGITS 5-3 




DIGITS 2-4 




64 


16.3 


292 


38.4 


101 


33.3 


206 


16.6 


63 


13.7 


216 


24.9 


90 


16.9 


154 


38.0 


54 


12.8 


253 


40.6 


97 


14.6 


146 


20.4 


55 


14.0 


177 


20.0 


81 


13.5 


139 


13.1 


83 


21.0 


218 


23.3 


52 


17.3 


127 


13.1 


68 


29.9 


183 


10.0 


57 


19.4 


119 


13.7 


68 


18.9 


180 


7.8 


64 


14.2 


113 


16.4 


63 


14.8 


190 


9.4 


70 


11.6 


124 


20.6 


47 


9.5 


221 


21.7 


73 


13.0 


212 


22.5 


46 


8.8 


206 


18.1 


89 


13.9 


210 


7.5 


46 


7.8 


201 


8.6 


80 


16.8 


221 


15.6 


50 


15.5 


181 


10.5 


78 


14.2 


177 


20.3 


33 


8.6 


202 


24.4 


78 


10.8 


162 


15.4 


30 


5.2 


229 


24.5 


82 


11.1 


101 


26.6 


33 


5.3 


193 


14.3 


66 


12.6 


119 


13.0 


35 


7.3 


192 


18.5 


62 


11.9 


116 


17.6 


83 


11.8 


189 


13.1 


43 


9.4 


114 


14.1 


67 


9.4 


184 


8.7 


39 


12.5 


92 


14.3 


84 


11.2 


194 


8.3 


39 


7.7 


83 


9.5 


77 


9.0 


187 


15.1 


37 


7.5 


81 


14.2 



A Study in Practice and Habit. 27 



ANALYSIS OF RESULTS. 

In exp. II. there is in certain cases a sudden drop in the reaction- 
time to approximately half that of the preceding group. For F., on 
digits 1-5, the series runs along consistently above 130 s., then drops 
suddenly to 72 s. Then it holds above 120 s. } and again drops sud- 
denly to 93 s., but following this, it runs to a high average again, then 
suddenly drops, and continues to a low level. This drop occurs in 
the same series with M. F. maintains the consistently low level 
with a slow decrease under 5-3, but for M. this reaction is hard, and 
the practice was not long enough to reach this stage. F. maintains 
this low level throughout the remainder of his exp. II; but for M. in 
series 2-4, it comes only at the end of prolonged practice. For H. and 
Y., the fluctuations from low to the high levels exhibit, which reac- 
tions were hardest for each subject. Y. found series 2-4 exceedingly 
hard, but, excepting this series, continues the low level throughout the 
remainder of exp. II. H. strikes the high or low level, according to 
the hardest series. 

F. hit upon the low level at odd times, but did not make use of it 
until late in the experiment; whereas, M. hit upon the same low level, 
and continued to use it, but at times varied unconsciously with the 
high level. As in the case of Y., once the subject chanced upon the 
low level, and became conscious of the quicker reaction, he used it 
throughout the remainder of the experiment. This new way of making 
the reaction was accidentally struck, and used several times, before it 
was consciously adopted. 

On the lower level, the subject had adopted a different method of 
reacting from the higher level of reaction time. At the beginning the 
double action was made as two successive taps, the first digit being 
lifted before the descent of the second digit. The subject found him- 
self unconsciously neglecting the separate taps, and running the two 
together. On the down stroke of the first digit, instead of waiting for 
the ascent of the first before the down stroke of the second again, the 
down stroke of the second was begun simultaneously with the up stroke 
of the first. The subjects were allowed to persist in the second method 
and adopt the low level, since piano players by no means wait for the 
ascent of the preceding digit before the down stroke of the second in 
piano playing. This fact is more fully discussed under exp. III.* 

The mean variation gives the complete study of the regularity in 
terms of the time element, and its influence is discussed under exp. 
III. It is well to note here, however, that as the reaction- time is re- 
duced, the possible mean variation is also reduced. This fact modifies 
the effect of the mean variation for purposes of comparison. Where 
the reactions are as high as 1,500 s., the possible mean variation is 
much larger than it can be when the average is only, say 75 s. The 
probable mean variation will therefore be much smaller in the case of 
the shorter reactions. This fact holds good in all the ordinary reac- 
tion-time experiments, as well as my own. (Cp. W. S. Johnson, Prac- 

*Cp. p. 36. 



28 A Study in Practice and Habit. 

tice and Habit, p. 56.) Other facts in these tables are fully discussed 
in connection with Exp. III. 

EXPERIMENTS III AND IV. 

Subjects: Four subjects, namely, H., F., Y. and M., reacted in this 
experiment. Each subject made 100 reactions for each day's practice, 
with rest periods between each 25 reactions to prevent fatigue. In 
some cases the rest period was prolonged. In exp. Ill, they were in- 
structed to wait for the signal for each reaction, but they were to make 
no calculations of the numbers. This rule was sometimes disregarded, 
but the distraction was offset by increased effort to hold the attention 
to the task. The gain in isolating the subject is not merely from dis- 
traction of calling numbers, sounds of the instruments, etc., but also 
to cut off possible interruptions. The subject was given the series at 
the beginning, and complete knowledge of his results. 

Conditions of the Experiments. In exp. Ill, the signal was calling 
the chronoscope numbers, but in exp. IV, it was a telegraph sounder, 
and the subject was isolated. One click was signal for each reaction, 
and three clicks meant the end of the group. A comparison enabled 
to make a study of distraction in analyzing the results. The experi- 
menter had two assistants, one of whom noted mistakes, as the mark- 
ers recorded them on the kymograph. A tab on the chronoscope and 
kymograph records was taken at the end of each 25 reactions, and dis- 
crepancies located before the experiment proceeded. The recorder 
marked every 5 reactions, making it easy to parallel the records, and 
also indicated different sorts of errors with introspections and physi- 
cal condition of the subjects. * 

The order of the series did not correspond with the order of the keys 
on the keyboard, but with the order in which the keys were struck. 
Thus key 1 was connected with marker 1, key 5 with marker 2, and so 
on for exp. Ill; the same relation being sustained in exp. IV. Thus 
when 1-5-3-2-4 was struck on the keyboard, the markers descended 
1, 2, 3, 4, 5 on the kymograph, making the record easier to read, and 
since the order of striking and their attachments were known connec- 
tions, no confusion resulted from this change. The name, number 
of the series and the date was written on each record, and the rest 
periods indicated by "R," and if any interruption, or breakdown oc- 
curred, the fact was also noted on the record. The apparatus worked 
smoothly, so that by careful adjusting, these interruptions were re- 
duced to a minimum, and during the last month of experimentation 
no such interruption occurred. 

Before the beginning and at the close of experimentation each day, 
the chronoscope time was checked for 100 s., with the pendulum for 
20 reactions, the piano-playing instrument being detached. The dif- 
ference in the chronoscope reading after three hours of experimenta- 
tion averaged less than 1 s., and the mean variation, while varying 
from day to day, averaged about .5 s. and never exceeded 1 s. This 
check on the chronoscope time gave considerable accuracy to the re- 
sults, and makes the study of the regularity from mean variations 
highly exact. In some instances, on special trial, as many as 24 re- 



A Study in Practice and Habit. 29 

i 
actions were taken in pendulum readings with the mean variation at 

Zero. As a rule, there was a fall of less than 1 s. between the begin- 
ning and the close of the three hour experimentation period. 

The tabulation of the results gives the date, the serial order of the 
reactions for groups of 25, the average reaction-time for each group 
with the mean variation. The total of errors furnishes a check upon 
the reaction-time. The various kinds of errors are separated out for 
detailed study, and these fall under three heads: 1. Duplications; 2. 
Omissions; 3. Out-of-order. The errors of omission explain them- 
selves, i. e., failure of the subject to strike one or more keys in reacting. 
If a key was struck before or after its serial order, it was recorded out- 
of-order, but if the regular order was preserved for 5 taps, and one or 
more keys struck twice (making 6 or more taps), causing a "double," 
the inadvertent stroke was a duplication. The distinctions preserve 
different errors and the significance of their several causes. 

The order of depression of the digits in exp. Ill was 1-5-3-2-4 suc- 
cessively; and for exp. IV, 1-4-2-5-3 successively. Each subject re- 
acted 1,500 times in exp. Ill; but an interval of six weeks passed be- 
tween the practices of the first 1,200 reactions and the last 300, for 
reasons indicated in the analysis. In exp. IV, 1,500 reactions were 
made by F. and Y., and 1,400 for H., who was absent one day; but M., 
attending twice a week, obtained only 1,200 reactions. In exp. Ill, 
practice periods were twice per week for all subjects alike, except the 
last week after the interval, when three periods of practice were given 
in one week with all subjects attending. 

The results of experiments III and IV are tabulated as follows: 

Tabulation of Successive Action of Digits, the time order series in exp. Ill, being 
1-5-3-2-4; in exp. IV, 1-4-2-5-3. The average of the reaction-times and the Mean 
Variations are computed on the basis of groups of 25 reactions. The errors are 
recoided under 1. Duplications; 2. Omissions; 3. Out-of-order; 4. Total of Errors. 



30 



A Study in Practice and Habit. 



TABULATION OF EXPERIMENT III (1-5-3-2-4) 




SUBJ 


. H. 








SUBJ. F. 


Date 


Ave. 


M.V. 


Dup 


Om. 


0.0. 


T.E. 


Date 
1-16 


Ave. 


M.V. 


Dup 


Om. 


0.0. 


T.E. 



1-16 


643 


25.2 


4 








4 


772 


107.0 











tt 


554 


26.2 
















631 


44.0 














u 


518 


43.1 
















617 


75.0 


1 








1 


(I 


496 


16.6 
















560 


58.0 


1 








1 


1-20 


473 


20.2 





1 





1 


1-19 


703 


92.0 


1 





1 


2 


u 


467 


22.3 


2 








2 




585 


24.6 








1 


1 


« 


480 


17.9 
















518 


49.5 


1 





1 


2 


a 


427 


22.0 


1 








1 




544 


48.3 


6 





1 


7 


1-23 


436 


32.0 














1-23 


594 


66.0 


2 








2 


(< 


430 


12.3 
















589 


46.2 














<< 


415 


9.9 


1 








1 




533 


35.4 














a 


417 


14.8 
















545 


25.5 














1-27 


423 


29.4 














1-27 


511 


49.4 


3 


1 





4 


« 


414 


15.8 
















520 


24.2 


1 








1 


« 


413 


13.1 
















510 


62.8 


3 


4 





7 


<< 


436 


17.8 
















504 


46.9 


4 








4 


1-31 


410 


20.2 














1-31 


471 


33.9 


2 





1 


3 


<< 


407 


13.0 
















512 


36.4 


2 








2 


C( 


390 


18.8 
















497 


44.1 


4 








4 


u 


360 


13.4 
















526 


48.6 


1 





1 


2 


2-3 


384 


17.3 














2-3 


488 


38.5 


2 








2 


« 


398 


14.0 
















477 


36.4 


10 








10 


<« 


386 


10.0 
















413 


43.6 


1 








1 


« 


399 


13.6 
















432 


35.6 


3 








3 


2-6 


365 


18.5 














2-6 


416 


56.2 


5 








5 


(< 


348 


15.4 


1 








1 




433 


56.9 


3 








3 


<< 


360 


12.4 


6 








6 




428 


47.4 


1 





1 


2 


tt 


363 


16.7 
















517 


66.4 


2 





1 


3 


2-10 


366 


21.4 














2-9 


433 


40.9 





1 





1 


i< 


340 


7.2 
















407 


29.3 


2 


1 





3 


<< 


328 


15.5 
















423 


31.4 


3 





1 


4 


« 


343 


23.5 





3 





3 




403 


24.8 


1 








1 


2-13 


359 


13.2 


1 








1 


2-13 


423 


20.4 


2 





1 


3 


t( 


352 


18.6 


3 








3 




386 


23.2 


3 








3 


a 


330 


14.6 
















361 


20.4 


2 








2 


it 


323 


9.9 














" 


375 


18.5 










1 


2-16 


345 


13.4 


1 








1 


2-16 


352 


27.1 


2 








2 


<< 


330 


14.8 














i " 


319 


18.9 


2 








2 


■< 


335 


6.7 


1 


1 


1 


3 


1 " 


366 


21.0 


2 





1 


3 


« 


348 


14.7 


1 





1 


2 


i " 


339 


12.7 


2 








2 


2-20 


383 


16.5 


1 








1 


2-20 

i 


336 


20.3 


1 


1 





2 



A Study in Practice and Habit. 



31 





EXPERIMENT III— Continued. 






subj. : 


H. 






SUBJ. F. 










Date 


Ave. 


M.V. ] 


Dup 


Om.t 


3.0. r 


r.E. 


Date 
2-20 


Ave. 


m.v. : 


Dup 


Om. 0.0. T.E. 




2-20 


358 


14.2 














311 


16.0 


1 








1 




it 


372 


6.5 














tt 


302 


24.3 
















it 


380 


13.5 





1 





1 


it 


326 


30.4 


2 





1 


3 




2-24 


342 


15.5 


1 








1 


2-23 


296 


17.1 


1 








1 




tt 


333 


16.9 














n 


274 


17.0 


1 








1 




it 


301 


17.2 


2 








3* 


it 


274 


14.5 
















a 


309 


18.0 


7 


2 


4 


13 ' 


i< 


290 


13.6 
















4-3 


532 


34.4 


2 





1 


3 


4-3 


379 


65.9 


2 








2 




tt 


464 


24.6 














a 


308 


19.2 


4 








4 




a 


388 


15.4 














a 


290 


8.8 


1 








1 




tt 


325 


8.4 














a 


256 


11.8 


2 








2 




4-6 


299 


43.0 


4 


1 


2 


' 7 


4-6 


275 


20.2 


1 








1 




(« 


273 


42.6 


1 





1 


2 


a 


261 


12.3 
















<( 


339 


21.2 








1 


1 


tt 


261 


15.7 
















it 


297 


20.1 














a 


272 


13.7 





1 





1 




4-7 


274 


34.5 














4-7 


271 


13.6 
















n 


305 


22.6 





1 





1 


a 


279 


14.0 
















a 


304 


17.4 





1 





1 


tt 


256 


13.8 
















tt 


293 


17.5 





1 





1 


it 


265 


16.8 


















SUB 


J. Y 




. 


SUBJ. M 


• 








1-16 


945 


69.6 


9 


o 1 


9 


1-16 


1167 


121.2 
















a 


867 


51.5 


1 








1 


tt 


1006 


51.4 
















<( 


888 


63.5 


4 








4 


a 


935 


52.8 
















tt 


869 


36.2 


2 








2 


n 


971 


158.6 


2 


1 





3 




1-20 


902 


30.0 


2 





1 


3 


1-19 


798 


121.4 


1 








1 




(< 


946 


75.0 


3 








3 


tt 


655 


53.9 
















it 


852 


44.4 


5 





1 


6 


it 


643 


34.3 
















tt 


862 


39.2 


10 








10 


tt 


602 


64.0 





1 





1 




1-23 


929 


33.6 


1 








1 


1-23 


774 


79.1 


1 








1 




it 


922 


64.8 


5 








5 


a 


654 


30.2 





2 





2 




a 


861 


21.0 


1 








1 


tt 


642 


46.3 
















it 


839 


31.1 


10 


1 





11 


it 


569 


38.1 





2 





2 




1-27 


835 


33.2 


5 








5 


1-27 


585 


63.2 
















(« 


855 


55.8 


7 


1 





8 


<( 


565 


39.8 


2 


2 


1 


5 




it 


831 


37.2 


4 








4 


tt 


519 


28.6 


1 








1 




a 


893 


74.9 


10 





3 


13 


tt 


491 


27.0 





1 





1 




1-30 


890 


110.6 


4 








4 


1-30 


697 


93.8 


3 





3 


6 




tt 


815 


46.8 


4 


6 





10 


a 


631 


75.5 


2 








2 




tt 


923 


108.9 


8 


2 





10 


tt 


527 


47.0 


1 


1 





2 




tt 


826 


36.5 


11 


1 





12 


<< 


484 


33.8 


2 


3 





5 



♦Reaction incomplete. 



32 



A Study in Practice and Habit. 



EXPERIMENT III— Continued. 




SUBJ. ^ 


r 




' 




SUBJ. 


M. 








Date 


Ave. 


M.V. 


Dup 


Om. 


0.0. 


T.E. 


Date 
2-3 


Ave. 


M.V. 


Dup 


Om. 


O.O. 


T.E. 


2-3 


858 


67.8 





2 





2 


529 


72.8 


1 


1 





2 




799 


44.9 


5 


1 





6 


u 


528 


59.4 


2 


4 





6 




746 


33.8 


10 








10 


tt 


477 


37.1 


1 


1 





2 




763 


47.1 


20 








20 


tt 


411 


38.1 


1 


5 





6 


2-6 


827 


37.9 


6 


2 





8 


2-6 


405 


40.4 


4 








4 




757 


94.3 


11 


1 





12 


« 


329 


39.7 
















691 


53.1 


4 


1 





5 


n 


320 


68.7 


2 


2 





4 




604 


108.0 


9 


1 





10 


u 


341 


30.2 





6 





6 


2-9 


798 


37.8 


6 


2 





8 


2-10 


346 


30.1 


2 


5 





7 




696 


40.7 


8 


4 





12 


H 


346 


33.6 


4 


4 





8 




726 


43.6 


13 


5 





18 


tt 


389 


43.0 


3 


4 





7 




693 


22.3 


11 


3 


1 


15 


it 


379 


51.1 


2 


1 





3 


2-13 


650 


70.4 


9 


3 





12 


2-13 


364 


20.5 
















680 


85.6 


12 


3 





15 


it 


289 


45.6 


1 


1 





2 


" 


621 


40.2 


15 


2 


1 


18 


<< 


277 


24.4 


2 


4 





6 




610 


42.2 


8 


3 





11 


tt 


245 


26.2 


1 


4 





5 


2-17 


660 


23.6 


6 


4 





10 


2-16 


240 


36.2 


7 


9 


4 


20 




625 


25.5 


7 


2 





9 


<< 


211 


35.3 


6 


16 


2 


24 




619 


59.2 


8 


6 





14 


u 


162 


32.8 


4 


14 


4 


22 




672 


54.0 


6 


6 


1 


13 


it 


96 


29.9 


4 


16 


1 


21 


2-20 


713 


65.9 


20 


15 





35 


2-20 


210 


82.1 


23 


22 


1 


46 




862 


48.8 


22 


6 





28 


u 


324 


21.7 


17 


2 


1 


20 


" 


776 


49.2 


15 





1 


16 


a 


267 


44.8 


14 


2 


2 


18 




769 


51.0 


8 





1 


9 


n 


249 


58.2 


10 


18 





28 


2-24 


787 


32.9 


8 


2 


1 


11 


2-23 


423 


41.7 


3 





1 


4 




812 


15.6 


1 








1 


u 


340 


45.3 


15 








15 




808 


17.0 


1 








1 


tt 


288 


12.8 


20 


9 





29 




796 


36.1 


4 








4 


tt 


905 


69.2 








1 


1 


4-3 


540 


28.5 


1 








1 


4-3 


382 


63.5 


4 


6 





10 




515 


29.9 














<< 


260 


115.8 


5 


11 


1 


17 




521 


22.6 


2 


o 





4 


u 


185 


71.8 


6 


8 





14 




486 


20.9 


6 


2 





8 


(< 


340 


92.9 


5 


2 





if 


4-6 


523 


49.5 


5 


1 


1 


7 


4-6 


569 


90.3 


2 


2 





4 




502 


29.0 


6 





2 


8 


n 


345 


95.2 


1 


4 





5 




472 


19.3 


3 


3 


2 


8 


a 


259 


62.5 


5 


9 


1 


15 




461 


41.0 


2 








2 


a 


306 


117.2 


o 
O 


7 


1 


11 


4-7 


403 


72.5 


4 


1 


4 


9 


4-7 


497 


72.3 


2 


2 





4 




413 


48.3 


2 


5 


1 


8 


it 


390 


80.2 


2 


1 


1 


4 


" 


355 


40.5 


14 


8 


4 


26 


n 


276 


54.9 


4 


2 





6 




422 


93.8 


5 





2 


n 
1 


tt 


176 


36.2 


3 


15 





18 



A Study in Practice and Habit. 



33 







TABULATION OF EXPERIMENT IV. 










SUBJ. F. 






SUBJ. 


Y. 








Date 


Ave. 


M.V. 


Dup 


Om. 


O.O. 


T.E. 


Date 
2-27 


Ave. 


M.V. 


Dup 


Om. 


O.O. 


T.E. 


2-27 


601 


100.1 


4 








4 


1014 


32.0 


1 








1 


<< 


606 


64.3 


3 








3 


it 


1077 


55.3 














<< 


583 


81.7 


2 


2 





4 


a 


1005 


24.5 


3 








3 


tt 


635 


82.3 


2 


1 





3 


a 


987 


21.0 


2 








2 


3-2 


527 


38.3 


5 





1 


6 


3-2 


924 


32.0 


2 








2 


tt 


532 


61.0 


3 


2 





5 


a 


906 


14.2 


4 








4 


11 


507 


86.6 


6 


1 


1 


8 


a 


886 


32.4 


4 








4 


a 


525 


61.3 


5 


1 





6 


a 


890 


36.2 


14 








14 


3-3 


470 


53.4 


5 








5 


3-3 


948 


48.6 


3 








3 


<< 


438 


29.9 


10 


2 





12 


a 


882 


27.9 


7 








7 


t. 


824 


22.0 





1 





1 


a 


868 


13.7 


1 








1 


n 


787 


32.1 














a 


847 


12.2 


3 








3 


3-6 


681 


47.8 


1 








1 


3-6 


875 


11.5 


3 








3 


«< 


542 


49.8 














a 


851 


18.2 


5 








5 


<< 


481 


36.9 


7 


1 


3 


11 


a 


854 


17.4 


3 








3 


a 


875 


44.8 


3 








3 


a 


842 


18.3 


1 








1 


3-9 


895 


68.9 


1 


1 


1 


3 


3-9 


870 


29.0 


2 








2 


« 


911 


27.0 














a 


818 


21.6 


2 








2 


<< 


887 


22.6 














a 


868 


41.9 


5 


1 


1 


7 


« 


772 


41.8 














it 


760 


16.9 


3 








3 


3-10 


485 


46.6 


2 








2 


3-10 


712 


62.0 


16 








16 


it 


432 


39.5 


7 


2 


1 


10 


a 


675 


45.0 


15 








15 


a 


500 


37.5 


2 








2 


a 


662 


28.4 


10 


4 





14 


a 


499 


70.4 


15 


3 


2 


20 


a 


691 


32.9 


7 


5 





12 


3-13 


429 


35.0 


11 


2 


2 


15 


3-13 


813 


16.0 


1 








1 


tt 


481 


53.7 


9 


2 


2 


13 


tt 


762 


25.6 


3 








3 


a 


461 


52.2 


9 





2 


11 


a 


772 


17.8 


5 








5 


a 


386 


41.6 


8 


1 





9 


a 


740 


13.5 


2 








2 


3-16 


385 


48.5 


10 


1 





11 


3-16 


738 


16.2 


6 








6 


<< 


384 


55.6 


15 


2 


6 


23 


a 


717 


13.8 


4 








4 


it 


456 


51.6 


8 


1 


7 


16 


it 


680 


12.5 


11 








11 


a 


469 


54.6 


4 





1 


5 


.a 


685 


11.7 


6 








6 


3-17 


367 


30.8 


18 





2 


20 


3-17 


761 


18.8 


6 








6 


<< 


461 


58.9 


13 


1 


1 


15 


a 


707 


15.0 


7 








7 


<< 


617 


53.6 


6 








6 


a 


741 


30.4 


5 








5 


a 


477 


52.0 


11 








11 


a 


628 


30.6 


8 








8 


3-20 


453 


56.6 


21 





1 


22 


3-20 


510 


35.6 


10 


1 





11 


<. 


676 


98.6 


15 





3 


18 


a 


535 


25.1 


11 


2 





13 


<< 


744 


27.4 


3 








3 


a 


524 


52.0 


10 


2 





12 


«< 


726 


21.7 


3 








3 


a 


680 


98.2 


9 


3 


1 


13 



34 



A Study in Practice and Habit. 









EXPERIMENT IV- 


-Continued. 










SUBJ. F. 






SUBJ. 


Y. 








Date 


Ave. 


M.V. 


Dup 


Om. 


0.0. 


T.E. 


Date 
3-23 


Ave. 


M.V. 


Dup 


Om. 


0.0. 


T.E. 


3-23 


820 


41.3 


1 


1 


1 


3 


584 


17.7 


3 








3 


tt 


795 


24.2 


2 


1 


1 


4 


a 


540 


40.3 


2 


3 


1 


6 


it 


703 


35.8 


2 





1 


3 


<i 


540 


22.0 


13 








13 


it 


613 


38.2 














a 


611 


136.9 


6 


2 


2 


10* 


3-24 


425 


30.3 


1 








1 


3-24 


626 


18.8 


3 








3 


u 


421 


31.5 


6 








6 


tt 


629 


31.5 














a 


381 


23.7 


4 








4 


a 


619 


16.1 


2 








2 


n 


398 


24.8 


7 








7 


c> 


592 


26.8 


2 








2 


3-27 


378 


23.6 


9 





1 


10 


3-27 


619 


33.4 


1 








1 


n 


365 


24.6 


12 


2 





14 


i. 


533 


27.3 


3 


1 





4 


d 


411 


35.5 


15 


1 





16 


i. 


485 


26.7 


4 








4 


tt 


429 


69.9 


19 








19 


a 


496 


25.4 


7 








7 


3-30 


419 


24.5 


7 





1 


8 


3-30 


512 


24.8 





3 





3 


" 


399 


33.2 


3 





1 


4 


i. 


478 


19.9 


2 








2 


a 


398 


25.2 


9 


1 





10 


it 


478 


28.1 


7 


1 





8 


t. 


388 


33.3 


3 








3 


it 


488 


28.0 


12 








12 


3-31 


376 


28.2 


8 





1 


9 


3-31 


574 


24.9 


1 


3 





4 


a 


345 


34.7 


8 





1 


9 


a 


551 


30.2 


2 








2 


tt 


326 


34.6 


12 


1 


3 


16 


a 


476 


26.9 


6 


1 


2 


9 


a 


657 


50.5 


7 





4 


11 


it 


563 


51.8 


6 





2 


8 






SU] 


3J. 1 


[. 










SUBJ 


. M. 








2-27 


629 


59.0 


4 





1 


5 


2-27 


774 


38.9 


2 








2 


n 


498 


27.9 


5 








5 


tt 


612 


63.5 


5 








5 


a 


542 


51.4 


2 








2 


a 


763 


99.2 


5 





1 


6 


it 


484 


29.0 


1 








1 


it 


775 


154.1 


8 


2 


1 


11 


3-2 


454 


40.6 


6 





2 


8 


3-2 


656 


27.2 


2 







3 


n 


428 


21.4 


2 








2 


tt 


661 


38.3 


9 




1 


11 


n 


407 


14.4 














tt 


726 


65.4 


6 


3 





9 


it 


386 


18.8 


2 








2 


tt 


700 


73.2 


2 







3 


3-3 


412 


15.4 


5 


1 


3 


9 


3-6 


697 


67.1 


1 







2 


tt 


412 


12.8 














tt 


594 


47.0 


1 








1 


a 


415 


21.5 


1 








1 


tt 


629 


48.9 


2 







3 


a 


398 


14.7 


2 








2 


— tt 


644 


80.9 


3 







4 


3-6 


430 


17.8 














3-10 


606 


68.2 


1 


3 





4 


t 


391 


23.4 














tt 


574 


47.2 


2 







3 


a 


368 


25.4 


4 


1 


1 


6 


a 


675 


67.3 


3 







4 


a 


380 


16.0 


1 








1 


tt 


671 


100.2 





3 





3 


3-9 


368 


13.3 














3-13 


581 


43.2 














tt 


347 


11.6 














tt 


612 


61.9 


3 


3 





6 


tt 


357 


9.7 


3 








3 


tt 


558 


42.6 


1 


3 





4 


it 


355 


13.5 


1 








1 


tt 


684 


57.6 


2 


4 





6 



*M. V. due to return to higher level under collapse. 



A Study in Practice and Habit. 



35 









EXPERIMENT IV- 


-Continued. 














SUBJ. 


H. 










SUBJ. 


M. 








Date 


Ave. 


M.V. 


Dup 


Om. 


0.0. 


T.E. 


Date 
3-17 


Ave. 


M.V. 


Dup 


Om. 


0.0. 


T.E. 


3-10 


404 


59.7 


8 





1 


9 


707 


39.3 














u 


370 


17.1 


1 


6 





7 


a 


679 


39.5 


1 








1 


a 


371 


19.6 


2 








2 


a 


753 


66.9 


3 


2 





5 


ti 


357 


14.1 


1 








1 


n 


645 


63.7 


4 








4 


3-13 


357 


20.2 


7 





3 


10 


3-20 


519 


58.9 








2 


2 


<< 


351 


16.7 


7 





3 


10 


tt 


488 


24.6 


3 


3 





6 


<« 


388 


49.9 


6 





3 


, 9 


tt 


494 


32.4 


4 


3 





7 


.< 


478 


110.3 


5 





2 


7 


a 


486 


23.4 


7 


5 





12 


3-16 


357 


12.6 


2 


2 





4 


3-24 


692 


19.3 


1 








1 


a 


353 


18.5 


6 








6 


tt 


698 


45.9 














it 


352 


11.9 


3 








3 


t. 


639 


75.7 


3 








3 


a 


360 


31.0 


8 


1 


1 


10 


t. 


635 


45.7 


3 








3 


3-17 


354 


29.1 


3 








3 


3-27 


585 


28.2 


4 








4 


tt 


324 


10.6 


2 





1 


3 


n 


483 


38.6 


4 


6 





10 


it 


305 


21.8 


2 


1 


2 


5 


tt 


487 


43.8 


4 


4 


1 


9 


it 


313 


17.2 


2 





1 


3 


n 


487 


48.3 


5 


9 





14 


3-20 


293 


16.1 


1 








1 


3-31 


500 


38.7 


2 


7 





9 


«< 


294 


14.1 














tt 


560 


28.7 


14 


3 





17 


it 


280 


16.2 














n 


610 


37.1 


7 


2 





9 


a 


261 


15.8 


2 








2 


tt 


557 


65.4 


4 


10 


2 


16 


3-23 


279 


12.2 




























u 


272 


13.6 


2 


1 





3 
















<( 


292 


36.0 


5 





2 


7 
















tt 


302 


32.4 


5 


1 


3 


9 
















3-27 


260 


26.8 


1 





1 


2 
















« 


257 


37.2 


10 


2 





12 
















<< 


271 


32.5 


4 


4 





8 
















tt 


281 


25.8 


10 





1 


11 
















3-30 


303 


16.4 


3 


1 


1 


5 
















<< 


297 


40.9 


6 





4 


10 
















« 


294 


34.7 


13 





4 


17 
















«< 


291 


36.7 


6 





3 


9 
















3-31 


411 


27.1 


3 








3 
















tt 


402 


22.2 


1 








1 
















tt 


402 


17.8 




























tt 


385 


25.6 





1 





1 

















36 A Study in Practice and Habit. 



ANALYSIS OF RESULTS, CONCLUSIONS AND GENERALIZA- 
TIONS. 

Distraction affects the mean variation mainly in any particular 
series, and the large fluctuations in reaction- time and the mean va- 
riation assignable to this cause are generally more frequent in the 1-5- 
3-2-4 series. Distraction takes two forms, 1. attention to objective 
conditions, i. e., an interruption, and, 2. mental calculation of the re- 
sults. One soon becomes accustomed to the noise of the instruments 
as a concomitant condition, which ceases to be a distraction, but the 
conditions enumerated above were eliminated in exp. IV. This latter 
kind of distraction is among the initial conditions which account for 
errors, and is a condition, which modifies the results, that is not so 
easily traced. Hence, if the pure effects of practice are the objects 
of study, such modifying conditions should be eliminated.* 

To the fluctuations of the practice curve, W. S. Johnson f assigns the 
following causes: "1. Lack of effort on the part of the subject; 2. local 
paralysis of the centers governing the muscles brought on by exercise ; 
3. mental paralytic strokes causing fluctuations which are generally- 
ascribed to mere fluctuations of attention; 4. general physiological 
fatigue of the whole body; 5. general mental fatigue." To these Book 
adds the effect of the breakdown stages, where the subject consciously 
adopts a slower rate. The large fluctuations of F. and M. also, Y., 
in some cases, are due to these causes. Book gives ' 'critical stages," 
noted in exp. II, and in experiments III and IV, where subjects vary 
between different methods of doing. (Cp. p. 44; also p. 24.) 

Another kind of fluctuations arises from a large class of phenomena, 
which Book styles ' 'short circuiting," by which he means a fusion by 
association of letters into syllables, syllables into words, etc. These 
associations are connected with the responses which follow, hence he 
subsumes them under "Habits of Manipulation." His approach is 
wholly from the standpoint of association, once he has shown the re- 
sults, (p. 24.) "There comes to be, if one may so phrase it, a sort of 
unconscious struggle for existence among the many modes of action' 
ending in the survival of the one direct and economic way of reaching 
the goal desired." While the most economic way of doing may never 
be reached (as he notes), yet it is true that some stage will finally be 
reached, which is more economical than any former method. Let 
us consider our own results. 

One observes three distinct "jumps" in the reaction-time, where the 
reduction suddenly becomes nearly 100 s. These are not periods of 
rapid improvement, but really "jumps" in the reaction-time which 
cannot possibly be due to the effects of practice. In the first stage, 

*Downey uses the method of distraction to throw into the foreground the two dif- 
ferent types of control processes in handwriting, which are 1. conscious control, 
2, automatic control. Distraction, she concludes (p. 151) is at best only an oscilla- 
tion of attention between two activities; or else, attention to one activity and refer- 
ence of the other to the realm of the purely reflex phenomena. This kind of distrac- 
tion, however, is materially different from sensory distraction, which modifies the 
results of practice. We preserve the distinction here. 

fSee Practice and Habit, p. 80. 



A Study in Practice and Habit. 37 

where the reaction-time was more than 650 s., the experimenter ob- 
served that subjects were using the successive tapping method of 
making five separate taps. Y., F. and M. used this method at the be- 
ginning of both experiments. F. drops it after the first 25 reactions; 
M. does the same after the second practice day; but Y. shows a gradual 
transition on February 6 in exp. Ill, and a sudden jump in exp. IV on 
March 17, and he never returns to it. F. fluctuates consciously be- 
tween the low and high levels, when he finds himself overspeeding, and 
making too many errors. In the transition from the tapping method 
to the Reciprocal stage (at 650 s.), there is always a corresponding 
large rise in errors and the mean variation. Once this level is adopted, 
the reaction-time and the mean variation slowly decrease again with 
gradual elimination of errors until about 400 s. is reached, when one 
of Bryan and Harter's "plateaus" occurs. H. begins his reactions in 
the Reciprocal stage; F. after the first group, frequently returns to 
the tapping stage to get his bearings, when errors become too frequent; 
M. drops into this stage about the third practice period; Y. reaches 
it about the close of the first part of exp. Ill with a large increase of 
errors. 

At the level of 400 s., however, is another break, or "jump," in the 
reaction- time to the level of about 300 s., where a third method of 
doing was struck by the subjects. In the Reciprocal stage, the reac- 
tions were made rhythmically in groups.* In exp. Ill, 1-5 and 3-2-4 
were run together with a short pause between. The getting back from 
digit 5 to digit 3 was found to be the difficult part of this reaction, but 
exp. II shows this difficulty to be more a mental than a physiological 
one. Again, the reaction of the digits was reciprocal in their relation, 
in that when one was on the up-stroke, the next in order was on the 
down-stroke. The reduction by practice in the method is, roughly 
speaking, from 650 s. to 400 s. in reaction- time and a corresponding 
reduction of the mean variation and gradual elimination of the errors. 
Below this point in the reaction- time, however, the subjects finally 
struck the Sequent stage. For H., this transition was more gradual 
than the rest, as F. and M. made sudden jumps in exp. Ill and F. in 
exp. IV. F. in exp. IV and M.in exp. Ill show a corresponding large 
increase of errors and the mean variation. The experimenter observed 
that the movement of the thumb, which began the reaction, was the 
cue for the descent of the other digits in their proper sequence. In 
other words, the reciprocal action of the digits became faster and 
faster, until it passed over into a stage, where the starting of the first 
digit set all of the other digits in motion at almost the same instant. 
Thus at the middle of the reaction, all the digits were in motion si- 
multaneously, but in their proper sequence, hence this was designated 
the Sequent stage. After this stage is reached practice becomes steady 
again in reducing the reaction-time, the mean variation, and the errors. 
The physiological limit for the correct response in exp. Ill seems to 
be about 250 s. with mean variation at 10-15 s. and practical elimina- 
tion of the errors. 

We note that these new methods of doing were unconsciously "fallen 

*Cp. p. 23. 



38 A Study in Practice and Habit. 

into" by the subjects, and that they invariably fluctuated from one to the 
other, until the more economical and rapid way of doing was finally 
adopted* If this is the fact, the process is not that of association, as 
Book and others assume. What is this process, which takes place in 
the nervous system outside of consciousness, with which the latter has 
nothing to do} Juddj gives us two principles of the formation of habit, 
which partially solve the problem. "First, there is a tendency for all 
parts of the nervous system which are active at the same time to be- 
come related to one another in their activity; and, second, there is al- 
ways a process of selection going forward by which these combinations 
which attend the end toward which the individual is working are pre- 
served and the others eliminated." Kirkpatrick| explains that the 
researches of Yerkes and Jennings reveal the same processes going on 
in the learning of lower animals. But the process of selection is not lim- 
ited to the preservation of the successful response and elimination of 
the unsuccessful. It applies equally to a larger class of activities, 
especially in human life, where skill is developed. In Co-ordination, 
therefore, these selective processes are at work, quite independent of 
Consciousness and the attendent associative processes, by which new, 
more skillful ways of doing arise, develop by practice, and become fixed 
in habit. Just as the inventor hits upon some new and novel idea, 
and works it out, these selective processes in co-ordination strike new 
methods of doing, "short-circuiting," as Book styles it, which become 
fixed in habit. Genetic psychology shows that the child makes many 
random movements, before hitting upon the right response, by which 
it succeeds in grasping the object in its ken. Trial and error persist 
throughout life, as the method of approach to new experiments in its 

*Swift observes this same phenomena in the tossing of balls, where he says, 
(p. 216), "In avoiding errors there was adaptation, apparently more organic than 
conscious, to conditions and often it was so delicate as to elude observation. B., for 
example, found himself tossing high in order to have time to recover himself from a 
difficult situation, and at another time he caught himself putting his body into a 
more alert position by slightly raising himself on this toes and making his muscles 
tense. Then he realized that he had been doing it for several days. So far as he 
could determine consciousness had no originating part in it." This he calls ''getting 
the knack." Swift notes the same phenomena in typewriting: "The new acquisition 
is well along however before it is discovered." (Psy. Bull., I, 1904, p. 305) Book 
(p. 31) notes these phenomena, but assigns to it only a minor and temporary signifi- 
cance. "All sorts of temporary helps and devices were used, and shorter and more 
direct methods of getting the fingers to the keys were constantly fallen into. But 
as the letter associations developed these devices were all slowly discarded." Never- 
theless, in the phenomena of "short-circuiting," he notes a "fusion" of the five stages 
in the lower orders of manipulation, and direction of attention to ever higher orders 
of activity. This fusion is a physiological process, though he does not so state, and 
while his "short-circuiting" is attributed to forming new association groups, there 
is some doubt as to the function of consciousness in this "fusion." Book gives us 
no light on this subject but only states the facts. In his summary (p. 71), he states, 
"A point worthy of special emphasis is that our learners, who were left without guid- 
ance of a teacher, worked out unconsciously a method of dealing with the special 
difficulties encountered in typewriting, which had the same result in the end." The 
value of conscious activity in learning would therefore according to this statement be 
only a matter of time difference in the process; the conscious activity would take the 
lesser number of practices. 

fPsychology, p. 223. 

JGenetic Psychology, chap. II. 



A Study in Practice and Habit. 39 

activity. In the three stages of adjustment in the formation of motor- 
habit in piano-playing, random movements are likewise eliminated. 
Errors, therefore, are not necessarily a sign of lack of progress, but just 
as much so, may be the sign of progress itself. With each new stage, 
a new set of random movements arise which have to be eliminated, 
and the adaptation already accomplished at the higher level begins 
again at the lower level. Such random movements are the prolific 
source of ' 'doubles," or errors of duplication. 

In all periods of rapid improvement there is likely to be a large in- 
crease of duplications. In both experiments, when the reaction-time 
is rapidly reduced, especially at the jumps, the most common errors 
are duplications. Duplications are most common with H., F. and Y., 
but M. has more omissions. But this difference with M. has a spe- 
cial cause,* and in stages of rapid development, duplications are 
equally numerous with the other subjects. Duplications are super- 
fluous, random movements in new, strange and uncontrolled situa- 
tions, and are rapidly eliminated by practice and attention. 

The direction of attention in eliminating errors presents a special 
case. The "sight method," where subjects watch the keys and give 
the whole attention, both visual and otherwise to the reacting, elimi- 
nates these errors by watching them, and giving the whole attention 
to the visual end of the series. f In cases, where a shift of attention 
was made to the motor end of the series, confusion invariably resulted 
with a corresponding increase of errors. This fact explains an other- 
wise unaccountable source of errors. Book's " touch method" was not 
investigated in my own experiments, and it is impossible to give the 
full significance of this fact. Certainly, in these experiments, the 
errors were eliminated in every case, because the subject gave his whole 
attention to the visual end of the series, and left the response to take care 
of itself. Sudden reductions in the error column are explained by this 
fact, particularly in the cases of F., Y. and M. On March 6, F. shows 
a reduction in errors from 7 to 3, where the reaction-time jumps from 
481 to 875 ; another example occurs just the day previous for the same 
subject. The subject became aware that he was overspeeding, and 
adopted a slower rate to eliminate the errors. A large series illustrate 
this point in the breakdown stages of Y. and M. in exp. III. 

Y. began to crowd his reaction-time Feb. 6-20 in the endeavor to 
make speed in the tapping method, causing a corresponding large rise 
in the error column and increase in the mean variation. Effort thus 
often directly interferes with practice. The Mean variations thus 
check the efforts of the subjects to speed, and in this respect give a 
more direct criterion than the plethysmograph method of Book. These 
errors of Y. are chiefly omissions and duplications, due to overspeed- 

*Cp. p. 41. 

■{This fact of attention to the visual end of the series was the special result of the 
eye-hand co-ordinations of MacMillan, where the center of the target was deflected 
by prisms, in striking with a pointer. He concludes that a numerical statement of 
these adjustments can be given. (Ibid. p. 15) Swift and Book both show that atten- 
tion to the visual end of the series and effort in overcoming old habits and bad habits 
are the only ways of eliminating errors. Attention and effort are watch-dogs of 
progress. This fact constitutes one chief function of consciousness in the Learning 
Process. (Cp. Book, pp. 91-99, also Swift). 



40 A Study in Practice and Habit. 

ing. A parallel case is presented in the case of M., Feb. 16-23. Y. is 
in the transition from the tapping stage to the reciprocal stage, but M. 
has crowded the physiological limit and is overspeeding. Y. over- 
crowded his speed in the tapping method, hence both Y. and M. fell 
into a breakdown stage. The experimenter observed this, and exp. 
Ill was taken off, exp. IV substituted, and exp. Ill reintroduceo dn 
April 3. With M., the breakdown was utter and complete, as after 
an interval of six weeks, she still shows the same tendency to over- 
speed. Moreover, the errors of Out-of-order become critical, so that 
in some cases, as 1-6 of the time, the correct reaction is not made. 
This condition shows a complete breakdown, where the physiological 
limit has been reached, and the effect of all previous practice was 
vitiated.* 

These breakdown stages are accompanied with such symptoms as 
extreme nervousness, loss of confidence, utter mental confusion, emo- 
tions of displeasure, and the ennui of the practice becomes almost un- 
bearable. The change of tasks effected a complete readjustment for 
Y., although his breakdown was by no means so critical as that of M. 
Duplications arise then in overspeeding, in transition periods, and from 
the naivete of the situation in the initial series. The rise and fall of 
duplications parallel the regulation of the speed. The same causes 
enumerated in exp. I of anatomical structure, contiguity and inter- 
ference hold good in the complex reaction, although other conditions 
have a more general effect. Other modifying conditions are partial 
paralysis of the control centers, due to the physical condition of the 
subject, and fatigue. The prolonged error-making is due to random 
movements at the initial stages of each new experiment or new method ; 
to overspeeding in the breakdown stages; to the loss of control under 
confusion, distraction, and the ennui of practice. 

Errors of omission are. due to (1) insufficient depression of the key; 
or (2) omitting to make any depression at all. They parallel the du- 
plications, and in general, the causes of these two classes of errors lead 
to exactly opposite kinds of error, in one case, an extra depression, and 
in the other case, no depression. In the first case, control breaks into 
superfluous activity, or random movement; whilst in the latter case, 
control secures no response in movement, or only a partial response. 
It is not strange that both these conditions should occur together in 
the breakdown stages, as they do. The difference is chiefly that dupli- 
cations are prominent in the initial stages of the tapping method, where 
omission is wanting. Omission sometimes exceeds duplication in the 
breakdown stages, the transition stages, and under states of distrac- 
tion, confusion, paralysis of the control centers, especially in the act 
of speeding (as case of M). 

Confusion plays a considerable role in causing omission, for if one 
error of omission occurred in any group, more of the same sort were 
likely to occur in that group, usually several in succession. The fact 
that omissions usually occur in groups! and on the same digit is note- 

*Bair (p. 42) notes that at too fast a rate, laws of chance operate, and the more 
rapid the rate, the more errors and hence longer practice to eliminate them. 

f Swift notes the persistence and regular recurrence of mistakes; also that they 
come in bunches. (The Learning Process, p. 310). 



A Study in Practice and Habit. 41 

worthy. M. exhibits all her omissions on digit 5. In exp. I, this 
digit proved muscularly weak, and needed greater innervation from the 
control centers to make the proper reaction. In speeding, this made 
her specially liable to errors of omission, and the summary shows the 
largest number of omissions for M. on the fifth digit. Insufficient 
innervation caused nearly all the omissions of Y., F. and M. The 
successive descent of the digits was made so fast that the control cen- 
ters were insufficiently automatized to make the whole reaction and 
broke down. F. had many errors of omission, especially in the harder 
experiment (IV), while in exp. Ill, his records are fairly clear of such, 
and they were not due to speeding, but to local causes. H. made 
few omissions, all due to local causes with but little effect on his pro- 
gress. Omissions are more closely related to the control centers than 
duplications, anf have not so great a multiplicity of causes. Save in 
the case of M., omissions are by no means as numerous as duplica- 
tions. 

Errors of out-of-order occur usually in large groups, either at critical 
and breakdown stages, or on certain days. This class of errors con- 
stitutes the most serious impediment to practice, as they involve a 
wrong response and relate directly to the control centers. In this regard, 
these errors stand apart from the other two classes. Out-ot-order 
means only one thing, i. e., a temporary paralysis of the control cen- 
ters, interfering with their proper functioning. Sometimes this state 
lasted for three or four successive reactions, accompanied by a multi- 
plicity of duplications. The introspection of such states as this reveals 
the utter loss of ability to function, and general mental confusion. This 
state may affect one reaction, or may occur periodically for one day 
or for several days. In the latter case, they always appear in groups 
of several in succession.* As the subject expresses it, "It seems like I 
can't get it right ; my fingers won't move." Out-of-order is sometimes 
due almost wholly to the physical and nervous condition of the sub- 
ject on one day. If extended over several days, or several periods, 
overspeeding causes the cells to function improperly ; but in breakdown 
and critical stages, it accompanies the general pathological condition 
of the subject, when such paralysis is liable to appear at any moment in 
reacting. Certain subjects seem to be liable to sudden momentary 
seizures of such nervous paralysis, which recurs at unexpected intervals. 
Whether it affects one reaction, or several in succession, the psycho- 
logical accompaniments are always the same, i. e., general mental 
confusion and utter loss of control. As a rule, subjects rarely hit the 
keys out-of-order, however often duplications and omissions are made ; 
but at certain stages of highly nervous tension, reaching almost to emo- 
tional disorder in the breakdown stages, such errors invariably occur, 
and always with the above-named psychological accompaniments. 
From introspection, observation, and analysis of the results, one is 
convinced that this kind of errors, i. e., Out-of-order, have to do wholly 
with paralysis of the control centers, on the functional side, and with 
confusion, on the mental side. 

Control of response in habit-formation is intimately connected with 

*Cp. p. 23. 



42 A Study in Practice and Habit. 

another large field of relations. In piano playing, there develops a special 
"touch" or "feel" of the keys, derived directly from sensations of con- 
tact in making the depressions. In my own investigations the sub- 
jects complained that the "touch" of the piano-playing instrument, 
while nearly like, was somewhat different from the touch of the regular 
piano keyboard. This difference is explained by the tension of the 
key depending upon a spring, not upon a weight at the end of the 
lever, as in the piano, although the force required to depress down the 
whole excursion of the key was exactly the same in both cases. This 
fact shows the keen sense of difference derived from sensations of 
touch. James* shows how these sensations become a highly organized 
complex, associated with the centers of response in a highly organized 
system of control, and diagrams the physiological scheme of this re- 
lationship in detail. He shows that this system, or complex of sen- 
sory experiences, associated with response in movement is what keeps 
the process going its customary round, even while the attention is 
otherwise engaged ; they give a continuous report to the consciousness. 
We only dimly feel that we are engaged in a given habitual activity, 
such as walking, but the moment a wrong movement is made, these 
sensations of contact and movement call instant attention to the fact. 
Attention restores the balance again, once more the habitual adjust- 
ment is set merrily going its round again, and continues until attention 
interferes with the activity, and it ceases. f 

This factor of the habitual touch of the instrument lies behind all our 
introspections, our perceptions of errors, or of wrong response. Through 
the development of these sensation-complexes of definite muscular 
memory, originating from sensations of muscular activity, the pro- 
cesses of control are made possible, as well as correction of errors by 
the subject. In the touch method in typewriting, where sight is elimi- 
nated as a corrective factor, control depends wholly upon sensations 
of movement and contact in association with the centers of response. 

*Psychology, Vol. I, p. 116. Bair also refers to this fact (practice Curve, p. 57) 
that our habitual bodily adjustment recalls to us "the feelings or experiences usually 
connected with that adjustment." This class of facts constitute the "warming up" 
of Swift (p. 216) and the "cues" of grapho-motor anticipation of Downey (p. 6 fl.); 
but these authors do not seem to recognize its full significance in the process of con- 
trol. Book (pp. 105-108) mentions the warming up in his account of the psycholo- 
gical accompaniments; but misses the mark in attributing it to physiological accom- 
paniments of increased blood supply. Objectively, it is adjustment to the instru- 
ment, as a runner "gets his stride"; subjectively, a sense of ease, which sensory-motor 
reports give, as the "habitual bodily adjustment" is struck. 

fWoodworth in Accuracy of a Voluntary Movement, pp. 71-88 outlines a scheme 
of the relations of muscle and joint sensations to control, which constitute for him 
the "sense of movement", but he unfortunately neglects sensations of contact, 
which he states cannot give the proper basis of control. This "sense of movement" 
is ordinarily neglected, and not to be relied upon, at least, "until it has become 
drilled into a well-disciplined signal corps." This analysis furnished the explanation 
of Downey's "grapho-motor anticipation" and "sensory cues." But I submit that 
Woodworth does not wholly explain the "touch method" in typewriting, nor the 
"feel" of the piano key, nor the general facts of bodily adjustment by his "sense of 
movement." I feel therefore that my own statements concerning the sensations of 
contact not only supplement his theory, but also propose a class of facts, without 
which, the joint and muscle sensations, as part of this complex system of control, are 
incomplete. (Cp. Book, p. 15). 



A Study in Practice and Habit. 43 

In cases where the attention was given to the visual end of the series, 
as in my own investigations, the two methods are shown rather to 
interfere with than to help one another, for whenever the subject gave 
his attention to the motor end of the series, a larger number of errors 
invariably resulted. In other words, in the "sight method," the re- 
sponses are more intimately associated with the visual end of the time- 
order series, than with sensations of touch. This explains why cer- 
tain of Book's subjects were able to report large, detailed, introspec- 
tive accounts of their progress, more exact perhaps than in the present 
investigations. Book admits, however, that introspection is not the 
most reliable kind of evidence in the progress of learning, and must 
be frequently checked by the records. In my own investigations, 
the most important introspections were not at all present in the initial 
stages of the experiment, because the differences of response were not 
highly organized enough to call attention to themselves in the con- 
sciousness. Subjects trained in introspection were unaware for some- 
time of changes in methods of response, even to others calling atten- 
tion to the change. Mental confusion, resulting from errors of a 
striking nature, that occur in groups, arise from states of feeling 
aroused by sensations of contact. These sensations are prolific causes 
of errors of duplication and omission, occurring in groups. Where T. 
L. Smith* suggests reducing muscular memory to a laboratory prob- 
lem, in any series involving sensations of touch and movement, the 
"touch method" of Book would be employed, since the "sight method" 
complicates the problem. This circular action of contact sensations 
with the touch method, using direct associative processes for correct- 
ing errors, instead of referring it to the visual end of the series, shows 
that, although association with the visual series is easier than direct 
association, in the end, response is much quicker by the touch method, 
especially in typewriting, where complicated and accelerated processes 
of association are invloved. Such a high degree of association is also 
necessary in piano playingf , though not necessary in the two present 
experiments of single responses. 

In general, therefore, the Control Processes relate to complex sen- 
sations of touch, muscular movement, and strain in co-relation with 
the methods of response. From these reflex touch sensations, the 
co-ordinations receive a certain "set," either by direct association, or 
by reference to the visual end of the series, and thus errors are cor- 
rected. Reduction of errors and regularity of response constitute a 
complete record of the system of control in the co-ordination series. 
The time series tends to decrease with practice, perfecting co-ordina- 
tion in a given method of response, or selection of more economical 
methods of response at the "jumps" in the reaction-time. The regu- 
larity shows the fixing of the co-ordination processes in habit-forma- 
tion, in the approach of the time-order series to the physiological limit 
where the mean variation reaches a minimum with elimination of errors. 

In popular language, "control" is merely function in its relation to 
perfect co-ordination, fixed by habit-formation. Such control is 

*Amer. Journ. Psy., 1896, VII, p. 453. 
tRaif, Zeitschr. f. Psy., 24, 1900, p. 355. 



44 A Study in Practice and Habit. 

merely response to a stimulus from the environment, unobstructed 
along the fixed * 'paths" of Habit, either directly or indirectly, a kind 
of "circular action."* Interference may cause a conflict of activities,! 
or inhibitions associated with memories of a former unpleasant ex- 
perience, and so on. The "freedom of habit" leaves the attention to 
expend effort along other lines of endeavor, and in relation to Voli- 
tion, therefore, Habit has no other possible relation than the passive, 
i. e., "permission." 

Regarding the relation of one experiment to another, it was noted 
that exp. Ill was taken off in a breakdown stage, and exp. IV substi- 
tuted. After exp. IV, 300 additional reactions were taken in exp. Ill 
to observe the effects of the interval of time, and of the new experiment 
on the old. H. and F. sustained a slight loss in the interval, but rap- 
idly regained this with the practical attainment of the physiological 
limit for a perfect response. M. and Y. were in the midst of a break- 
down, and the change of tasks not only completely recovered Y. from 
the nervous breakdown and the corresponding slump, but during exp. 
IV, he reached the reciprocal stage of response, and consciously 
adopted it in the second part of exp. Ill, where his rapid progress prac- 
tically perfected the reciprocal stage on April 6. M. broke down com- 
pletely, and never fully recovered, but still exhibited the tendency to 
overspeed the physiological limit with corresponding disastrous conse- 
quences. When her attention was called to this fact, she complained 
that she could not refrain from overspeeding. Although fully deter- 
mined to control the situation, she fell into old habits of overspeed- 
ing before half of the practice period. Here is a critical case of prac- 
ticing the wrong response, and establishing it in the processes of Habit. 
On the final day, all subjects save F. became nervous trying to make 
good records, knowing it was the last period. Y., however, shows ap- 
proach to the sequent stage, and another week of practice would prob- 
ably have perfected this method. The principal effect of practice in 
one experiment on another is an increasing familiarity with the in- 
strument, and general training in methods of response. J The spe- 
cial practice of F. and M. in exp. II gave both advantage over Y., 
which the latter never overcame, while H. is prejudiced with his fa- 
miliarity with the piano, which explains his advanced progress through- 
out, although F. ultimately eclipsed him in perfecting exp. III. In 
changing experiments, there is no interference, as during exp. IV, no 
one reacted the order of exp. Ill, or vice versa. On the basis of this 
fact, one may lay down the Law of Correspondence as follows: Any 
series of responses of a given time-order in a series of practices, effects a 
corresponding decrease at the initial stages in the reaction-time of a dif- 
ferent time-order series, where the functioning organs in the two series 

*See Thorndyke's, Animal Intelligence, Chap, on monkeys. 

fDowney used this conflict of activities in grapho-motor anticipation and visual 
perception, which are just the processes of control built up by practice. 

{Johnson found piano-playing influenced tapping. Swift (Phys. and Psy. of 
Learning) says, "Skill in certain lines may be serviceable in other similar processes, 
but its value decreases as the difference between kinds of work increases, and in 
many cases, it is probably zero." Davis in Cross-education shows transference is 
mainly in parts with highly organized nervous interconnections, and training of 
attention and will. 



A Study in Practice and Habit. 45 

are the same. Vice versa, the methods of response, automatized in one 
time-order series, may be imported entire without a break into another series 
of a different time-order. This law holds good only where the physi- 
ological functions correspond, detail for detail, excepting the differ- 
ence in the time-order series. 

Previous investigators in the field of Habit have made a fad of con- 
structing the so-called practice curves. Scripture* has already pointed 
out that the term is a misnomer, suggesting the curve of improvement 
during a single period, as the "curve of practice," and the curve con- 
structed on group averages for successive sessions, as the "curve of 
Habit." But neither a curve constructed upon the decrease of reac- 
tion-time, nor the curve of errors diagrams the effects of practice on 
Habit. A curve of general improvement might be constructed on re- 
action-time, although with tables self-explanatory, diagrams are use- 
less. The practice curve originated with Bryan and Harter, and its 
form varies with the different scales adopted in its construction. Book 
sometimes blocked the averages, which method is open to fewer ob- 
jections of inaccuracy. In drawing the so-called practice curve, aver- 
ages of an arbitrary number of practices, or the number of reactions 
in an arbitrary length of time constitute the units of progress. These 
averages are located as points on the scale of a diagram, arbitrarily 
conceived, and between this series of points a line is drawn. The 
mean variation above and below the averages is neglected. What 
does the angle at each point, or the slope of the line, or the general 
curvature mean? The angle at any given point means nothing, nor 
does the curvature of the line between any two given points. This 
being true, the general curvature means nothing. The whole struc- 
ture is therefore meaningless and useless. Even the general tables are 
useful only after a careful study of the records in detail, supplemented 
by observations and introspections. The groups were chosen, because 
they represent reaction periods with definite rests between, and the 
averages of the errors and the reaction-time with the mean varia- 
tions only become meaningful as a basis of comparison in a long 
series of short practice periods. Of Bryan and Harter's plateaus, 
some explain them as periods of automatization, while others call them 
resting places of effort. f Investigators have cudgelled their brains 
to find a possible interpretation of this supposed flat place in the curve. 
But since the curve is meaningless, the "plateau" suffers the same 
fate. To sum up, there are three objections to drawing the so-called 
practice curve: 1. It is a misnomer; 2. the general curvature has no 

*Johnson, Practice and Habit, p. 67. 

fBryan and Harter called the "plateau" the period of automatization. Johnson 
calls it a "resting place in effort." It is significant that Bair's practice curves are 
without "plateaus." Swift attributes them to the ennui of practice, or "overshoot- 
ing the mark" in speeding. Book distinguishes between short plateaus, "breathing 
places" or temporary relaxations in effort, and real plateaus, due to 1. loss of interest 
with relaxation of effort; 2. excessive effort with accumulation of mistakes causing 
break-down stages. The "plateau" assumes that practice ought to bring steady 
improvement, but this does not follow. Changes are due to modifying circumstances, 
which cannot be totally eliminated. To study the pure physiological effects of 
practice is impossible. 



46 A Study in Practice and Habit. 

reference to the effects of practice; 3. the tabulation of the results is 
so clear and evident that diagrams are superfluous. 

From our survey of the general literature and these investigations, 
I wish to give not a summary, but a few general conclusions to obtain 
a clear conception of the meaning of a habit, and the chief contributive 
processes involved in its formation. These processes are subsumed 
tentatively under 5 heads, to make them central points of discussion. 

1 . Habit is related fundamentally to the association of a given stim- 
ulus to a response in movement in a given time-order series. Kirk- 
patrick notes the genetic relation to instinct, that without functions 
ready-made for response along certain general tracks, response would 
be impossible. The effects of innervation along these general tracks, 
however, are not specialized, for trial and error together with certain 
selective processes going on within the organism reduce random move- 
ments. This "blazing the way" for highly specialized function by 
conscious attention, where movement is made toward a certain end, 
in response to a given stimulus, is spoken of as "securing Control." 
A habit is therefore fundamentally related to a highly specialized re- 
sponse in movement to a given stimulus to attain a certain end. 

2. The above-named response is attained by repetition of the re- 
sponse to each new presentation of the stimulus. A series of such re- 
sponses, where attention is given to securing the desired end, is called 
Practice. Practice is the specific means by which habit-formation 
is accomplished; it is the vehicle of Progress. Each succeeding prac- 
tice steadily automatizes the co-ordination processes, until a highly 
complex and specialized response, or series of responses, in a given 
time-order series can be carried on with minimum attention. James 
remarks that this minimum attention is always present in the con- 
sciousness, if only the feeling that "everything is going all right." This 
minimum of attention to motor response is just the difference between 
a habit and a highly organized series of reflexes. 

3. Practice has four functions in habit-formation, association of the 
stimulus with the response, reduction of random movements, diminu- 
tion of the activity to a state of minimum attention, and specializing 
function to secure the desired end. Perfected association with per- 
fected co-ordination are the twin results of practice, the one on the 
conscious side, and the other on the motor side of response, as two 
different aspects of one process. Dewey contends that motor-re- 
sponse to a sensory stimulus is all one experience. However, certain 
processes go on outside of consciousness, which make for progress in 
functioning, quite as much as conscious choice. These selective pro- 
cesses perfect the co-ordination processes by securing more economi- 
cal responses, resulting in the various "stages" of progress, explained 
in experiments III and IV. Habit may therefore be regarded as per- 
fected association plus perfected co-ordination. Objectively, Practice 
reduces the reaction-time, the mean variation, and eliminates errors 
from the response. 

4. The co-relation of the regulative system with sensations of touch, 
muscular movement, strain and fatigue has already been reviewed at 
length. The co-relation of these sensations with their respective mem- 
ory centers is intimately associated with (1) the centers governing motor 



A Study in Practice and Habit. 47 

response direct, or (2) the visual end of the series in such experiments 
as typewriting or piano-playing. The reference of the attention to 
the one or the other of these association groups in practice constitutes 
the "touch" method or the "sight" method of response, in processes 
of control, correcting errors, and so on. This regulative system, as 
James remarks, is what enables the series of responses to keep going 
with minimum attention to each separate act. Were it not for this 
"short-circuiting" principle in habit-formation, dependent upon sen- 
sations of touch and movement, the sphere of our activities would be 
limited, indeed, and the progress of our activities slow, if every 
activity must successively occupy the center of attention. This fac- 
tor in the association-co-ordination chain is the basis of all progress 
and education, by which emancipation from the burden of detail in 
response and in all our activities is secured. 

5. Finally, what is the basal principle in the nervous system, which 
makes habit possible? James attributes it to the plasticity of the ner- 
vous system (p. 105), but this does not state the whole case. Doubt- 
less, the impression of any process in the nervous system is due to its 
plasticity, and the processes of habit-formation are dependent upon 
these impressions. But (as Judd, Kirkpatrick, Wundt, and others 
point out), Habit, like Memory*, is a retentive or fixing principle in 
the nervous system. Habit is not memory, however, and the distinc- 
tion lies chiefly in their antithetical relation to consciousness, in that 
Practice brings Memory each time more clearly into consciousness, 
while in Habit, it excludes the response to sensory experience more 
and more from the center of attention, until finally it drops out on the 
fringes of consciousness. Nevertheless, both Habit and Memory are 
due to the retentive principle in the nervous system in receiving im- 
pressions. 

*"Le memoire n'esfc, en effet, sous certains rapports, qu'une forme perticuliere 
de 1'habitude." (Bourdon, Recherches sur Thabitude, L'Annee Psy., VIII, 1901, 
p. 340). 



48 A Study in Practice and Habit. 



BIBLIOGRAPHY. 

Memory Investigation: 

Ebbinghaus, "Ueber das Gedachtniss", rev. in Am. Jour. Psy., 1889-9, p. 587 fl. 

Muller ans Schuman, "Experimental Beitrage zur Untersuchung das Gedacht- 
nisses", Zeitschr. f. Psy., VI, 2 and 3, p. 173 fl. 

Kuhlmann, "The Present Status of Memory Investigation," Psy. Bull., V, 1908, 
pp. 285-293. 

T. L. Smith, "On Muscular Memory," Am. Journ. Psy. VII, 1896, pp. 453-490. 

Practice and Habit (including skill in an occupation) : 

W. S. Johnson, "Practice and Habit," Yale Psy. Lab. Studies, VI, pp. 51-103. 

Bryan and Harter, "Studies in the Telegraphic Language," Psy. Rev. IV, 1897, 
pp. 27-53. 

Bryan and Harter, "The Acquisition of a Hierarchy of Habits," Psy. Rev., VI, 
1899, pp. 345-375. 

W. W. Davis, "Researches in Cross-education," Yale Psy. Lab. Studies, VI, 1896, 
pp. 6-50. 

D. P. MacMillan, "A Study in Habit," Uv. Chicago contr. to Phil., 1899, II, No. 
2, p. 11 fl. 

Exner, "Zur Kenntniss der Wechselwirkung der Erregung in central nervous- 
system," Archiv. f. d. ges. Physiol., 1882, XXVIII, p. 487 (ref.) 

Raif, "Ueber Fingerfertigheit beim Clavierspiel," Zeit. f. Psy., 24, 1900, pp. 252- 
257. 

Bourdon, "Recherches sur L'habitude," L' Annee Psy., VIII, 1901, pp. 327-340. 

J. E. Downey, "Control Processes in Modified Handwriting," Psy., Rev. mon. 
sup., No. 37, 1908. 

Woodworth, "Cause of a Voluntary Movement," Phil, and Psy. Studies, Garmon 
Commen. Vol., p. 339 fl. (ref.) 

Coover and Angel, "General Practice Effect of Special Exercise," Am. Journ. 
Psy., XVIII, 1907, pp. 328-340. 

Judd, "Practice without Knowledge of Results," Yale Psy. Studies, N. S. 1, No. 1 
Psy. Rev. Mon. Sup. 

Johnson, "Experiments on Motor Education," Yale Psy. Lab. Studies. X, 1902, 
pp. 81-93. 

Bair, "The Practice Curve," Psy. Rev. Mon. sup., V, No. 2, 1902. 

Bergstrom, "Relation of Interference to Practice Effect of an Association," Am. 
Journ. Psy., VI, 1894, p. 433. (ref.). 

Swift, "Psychology and Physiology of Learning." Am. Journ. Psy., 1903, pp. 201- 
251. 

Swift, "The Acquisition of Skill in Typewriting," Psy., Bull., I, 1905, pp. 295-305. 

Woodworth, "The Accuracy of a Voluntary Movement." 

Swift and Schuyler, "The Learning Process," Psy. Bull., IV, 1907, pp. 307-310. 

W. F. Book, "The Psychology of Skill," Uv. of Montana Pub., Series No. 1, 1908. 

General Reference : 

Stout, "Analytic Psychology, 1896, ch. IV, bk. II, pp. 254-281. 

Toulouse, Vaschide and Pieron, "Technique de Psychologie Experimentale," 
Paris, 1904, ch. 5, p. 227 fl. 

Judd, "Psychology," pp. 213-231. 

Kirkpatrick, "Genetic Psychology," 1909, p. 30; also pp. 11-126. 

Wundt, "Human and Animal Psychology," pp. 402-410. 

James, "Psychology," (advanced course), Vol. I, pp. 104-144. 

Yerkes, "The Dancing Mouse," chapters 12-16. 

Yerkes, "Habit Formation in the Crayfish," Harvard Studies, vol.1, pp. 565-579. 

Jennings, "Behaviour of the Lower Organisms," pp. 179-190. 

Holmes, "Evolution of Animal Intelligence," pp. 153-159. 

Morgan, "Introduction to Comparative Psychology," pp. 161-196. 

Angell, "Psychology," pp. 58-74. 

Baldwin, "Mental Development," pp. 203-208; 226-248; 452-467. 

Yerkes, "Animal Intelligence," especially chapter on "Circular Action in Mon- 
keys." 



LIBRARY OF CONGRESS £ 



020 199 785 9 



I 



Holling 



020 199 785 9 



Hollinger Corp. 
P H8.5 



